.

Three Phase Asynchronous Motor

OPERATION AND MAINTENANCEINSTRUCTIONS

0EY.460.072

Shenyan Electric Machine Co.,LTD

CONTENTS

1.Introduction …………………………………………………… 3

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2.Installation and adjustment ……………………………… 6

3.Electric connection and start-up ………………………… 16

4.Inspection and maintenance ………………………………… 21

5.Accessories ……………………………………………………… 38

6. Trouble shooting ………………………………………………40

7.Allowable temperature rise for asynchronous motor …… 46

8.Additional pages …………………………………………………47

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1. INTRODUCTION1.1 OutlinesThe present instructions are applicable to the operation and

maintenance of three phase alternating current asynchronous motors which are manufactured by Shenyang Electric Machine Co., Ltd.

For the basic electric characteristic parameters relevant to the motor refer to the documents attached to the machine and its nameplate, Data of foundation, main circuit and interfaces for auxiliaries refer to the outline drawing of the motor.

It is impossible for this instruction to include all problems relating to installation, operation, maintenance, etc. of the motor. For other problems which are not fully expressed in the instruction, you may communicate with our company directly, if necessary.

1.2 Product introductionAll three-phase asynchronous motors manufactured by Shenyang

Electric Machine Co., Ltd. are in conformity to LEC standards and current standard used in the country.

Optimization design of products is realized, since up-to-date measures of development are adopted. Therefore, the products are possessed of reliable mechanical and electrical performances. Stator winding of high - voltage motor adopts technology of Vacuum Pressure Impregnation (VPI) and therefore operating life of the motor winding is prolonged effectively. The construction of rotor winding of squirrel - cage motor is aluminium casting- type or copper bar type. Due to adopting special technological measures to ensure safety and reliable operating performance of them, motors produced by Shenyang Electric Machine Co., Ltd. have greater versatility. Products with different protecting levels can be designed and produced according to users' requirements.

1.3 General description1.3.1 Symbols are explained as follows1.3.1.1 The most common construction and installation for three -

phase asynchronous motors manufactured by Shenyang Electric Machine Co., Ltd. are IMB3, IM7211 and IMV1. (See Table 1.) (according to IEC34 -7).

Table 1IM B3 IM7211 V1

AbbreviationLetter of

Two end- shield type bearings

Two pedestalbearing,

Two end - shieldtype bearings

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internationalinstallation

With footing With footing Without footingWith a cylindrical shaft extension

With a cylindricalshaft extension

Shaft extension isDownward

Installed onfoundation

Installed onfoundation

installed on thebottom with flange

Sketch

1.3.1.2 CaseIn the installation site and service condition of motor, motor case is

possessed of corresponding protection form to prevent dust, foreign matters and water from entering into winding and other moving parts and to prevent operator from accidentally touching moving and rotating parts. Classification and mark of various protective type of case refer to IEC 34-5.

Marks of protection class consist of letters“IP”and two characteristic digits after the letters. The meanings of characteristic digits are listed in Table 2.

Table 2.Basic Mark IP

Abbreviation letters of international prevention．

The first

digit ， from 0 to

6

Prevent person from touching and prevent solid foreign matter from entering into interior of motor

The second

digit ， from 0 to

8

Protection level to prevent water drop from entering into motor to reach harmful degree

In general ， three-phase asynchronous motors manufactured by

Shenyang

Electric machine Co. ， Ltd. adopt the following protection levels ；

IP23，IP44，IP54 and IPW24.

The protection mark on the case of motor with additional device for

special climatic protection is expressed as“IPW”，such motor are suitable

for outdoor installation.

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1.3.1.3 CoolingVarious cooling circuits and cooling means of rotating electrical motor

are defined in IEC34-6.Symbols which express cooling means include letters“IC”and one letter

and two characteristic digits after“IC”to show various cooling circuits with different cooling mediums.

The most common cooling means of motor are identified with the IC and two characteristic digits.

The three-phase asynchronous motors generally adopt the following cooling means:

IC01，IC11，IC21，IC31，IC37，IC81W，IC151，IC611.

The meaning of mark for cooling means see Table 3.Table 3

Mark DescriptionIC01 self-cooled open-type motor with cooling fan mounted on the

shaft.IC11 self-ventilated motor with air inlet duetIC21 self-ventilated motor with air outlet duct1C31 self-ventilated motor with inlet and outlet ductsIC37 Motor with inlet and outlet ducts as well as independent or

separate

blower，or pressure source of cooling medium

IC81W Air-cooled and self-ventilated motorHeat exchanger (air-water) installed on the motorPower of water circulation supplied by independent pump or water system

IC141Totally-enclosed and fan - cooled motor with self- ventilation，

(with cooling fins in the case)ICl51 Totally-enclosed and fan-cooled motor with self -

ventilation(with cooling pipes in the case)IC611 Totally -enclosed and fan—cooled with self-ventilation heat

exchanger(air-air) installed on the motor1.3.2 Direction of rotation

When the letter order of terminal markings of the motor(U ，V，W or

U1，V1，W1，U2，V2，W2 …) are same as that of phase order of power

supply (L1，L2，L3)，the direction of rotation of the motor is clockwise as

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viewed from the end of main shaft extension．Accord to the condition , if

need counter-clockwise rotation ,please first get agreement from my company . Then reverse U and W as shown in Figure 2 .

Figure 1 Clockwise rotation as Figure 2 Counter-clockwise rotation viewed from driving end as viewed from driving end

In case the motor is two speed motor ，double voltage motor or high

speed motor with irreversible rotation ， refer to the relevant particular

direction of rotation and terminal marking in the outline drawing ．During

motor running，to reverse wire connection of power supply to make motor

rotate in reverse direction but brake is not permitted．

2.Installation and adjustment2.1 Goods receiving and handlingRefer to outline drawing and packing list to determine goods received

items and to check whether or not goods are complete.

Lifting rods and lifting holes must be used in all lifting work ．Lifting

and supporting at iron core laminations or winding are strictly

prohibited．When hoisting whole motor，hoisting rope should be used to

make the weight evenly distributed and supporting bar should

be used to prevent top cover from deforming ． When

installing，careless handling and hoisting with incorrect use of lifting rod

and hoisting hook would damage motor more seriously as compared with

the motor normally running for many years．When handling motor，take

care not to damage the winding.

Attention：When hoisting whole motor ，use of lifting lugs on the top

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cover is strictly prohibited，If heavier coupling or other attachments cause

unbalance of hosting ,hoisting rope must be added additionally to prevent motor from overturning .

Motors with medium and large capacity are often equipped with fixing devices for rotor to prevent rotor from moving in axial direction. When handling the whole motor, fixing device for rotor must be mounted. If fixing device is not mounted, damage of bearing would occur due to axial movement of bearing.

2.2 Storage2.2.1 Ordinary storageThe motor should be stored in a clean and dry place with covering on

it. If it is cold, moist or undergoing severe temperature variation in the storage place, the temperature of motor winding should be kept 5℃ above the environmental temperature to prevent it from dewing and absorbing moisture.

2.2.2 Temporary storageAlter motor is received and is not installed immediately, unpacking and

inspection should also be carried out as well as it should be stored in a room where it is clean, dry and with small temperature variation.

2.2.3 UnpackingRemove all package and non - permanent auxiliary devices of motor.

Clean away dirt on the shaft extension and the coupling with petroleum solvent and observe necessary safe precaution. For wound rotor motor, insulation should be filled between collecting ring and brush in order to prevent forming specks on the working surface of collecting ring.

2.3 Preparations before installationBefore installing motor, the following points should be checked.2.3.1 On the foundation platform, determine marks of position so that

center line of the unit and elevation of the foundation surface can be found out.

2.3.2 According to the outline drawing of the motor, check the foundation to determine proper positions of foundation pit (if any), cable, cable duct, busbar or ventilating pipe, and there is enough space to carry, out installation of the unit and its attachments.

2.3.3 Check the dimensions and position of foundation bolts as well as the elevation of the top of the bolts according to outline drawing.

2.3.4 Prepare enough quantity of leveling pieces and shims to ensure that base plate or base frame will not deform when installing them.

2.4 PositioningThe following factors should be considered when determining the

location of motor.2.4.1 The motor should be installed in the place with good ventilation.2.4.2 Attention should be paid to the air inlet mad outlet of the motor.

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Never make hot exhaust air entering into air inlet to cause repeated circulation or hot exhaust air directly entering into another motor.

2.4.3 Ensure that there is enough working space around the motor to facilitate motor disassembling, cleaning or inspecting.

2.4.4 When installing motor of slide bearing with oil ring, the shaft should be maintained in a horizontal position to avoid oil leakage and to ensure normal operation of oil ring.

2.5 FoundationFoundation must be rigid so that vibration of motor and degree of non

alignment for shaft line in operation can be decreased to minimum. It is better that foundation has a rigid concrete block with sufficient depth which is placed on a rigid ground. In case motor must be placed on a steel structure rather than a concrete foundation, the beam and frame should be supported with sufficient struts. (A common cause of vibration of motor is that when designing foundation, motor is installed on the high structure without sufficient consideration for vibration problem)

Footing surface of the motor should be placed on steel spacer or bed plate. The top surface of steel shims or plates must form a level surface and its elevation is slightly lower than the value of elevation obtained from the maximum distance between center line of motor shaft and footing surface. Before the footing or base plate are placed on the concrete foundation, the top surface of foundation should be made rough and washed thoroughly. Grouted layer of foundation should be carried out strictly according to the requirements to ensure solid foundation.

2.6 Installation of foundationIn case the motor manufacture does not provide spacers, they should

be fabricated with steel plate according to the following description.2.6.1 Proper hole should be made on spacer to adapt to anchor boll

mounting.2.6.2 There are enough sphenoid spacer and iron spacer ensure that

make pression about 20-40kg/cm2,the location of motor along anchor bolt and area of concentrative load ,as well as under support bar of base frame .

2.6.3 Installation of spacers used between base surface of motor and steel foundation surface should be properly filled up.

Rigidity of foundation and accuracy of contact between base surface of motor and foundation surface directly influence vibration of the motor when operating.

2.7 Procedure of installationAccording to type of motor protection, take care of surrounding

environment for installation. Open-type motor should never be installed in the hazardous, inflammable or dusty place.

2.7.1 The installation of heavy - duty motor (with pedestal bearing) is mainly introduced as follows.

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2.7.1.1 According to the position of horizontal and vertical axes of motor (generally center line of motor is chosen), two tensioned steel wires are set above the foundation with a certain height. Plumbs are hanged on the steel wires and used as reference for adjusting position of base plate.

2.7.1.2 While foundation bolts are mounted on the foundation, spacers are placed on the foundation surface and along the periphery of base plate, (Foundation bolts and spacers are provided by the customer.) as well as under support bar of base frame.

2.7.1.3 Remove bearing cover, bearing shoe, etc. on the pedestal bearing which has been fixed on the base plate. Lift base plate and pedestal together and put them on spacers. Adjust the longitudinal position of base plate by means of plumbs and adjust the horizontal position as well as height of base plate by means of spacers. After the position of base plate is adjusted , tighten foundation bolts immediately .Finally, recheck levelness with leveller. The tolerance of air bubble in the leveller should not exceed 1/2 graduation (1 graduation corresponds to 3mm inclination for lm length) and fix the spacers.

2.7.1.4 Rust-preventing grease filled in the bearings when delivering from the company must be rinsed. Wipe bearing shoe, bearing retainer of rotor, shaft extension, etc. thoroughly with a rag dipped with gasoline. A haft coupling or gear is sleeved at the end of shaft extension.

2.7.1.5 Carry out the installation of stator and rotor. The installation method of stator and rotor depends upon the capability of customer's hoisting equipment and at the same it is determined on long shaft short shaft of the motor. When hoisting ,pay attention to that the hoisting rope

should not touch the fan ， winding ,collecting ring ， bearing and shaft

extension．

a．Short shaft type：

For short-shaft type motor ， in case the customer has hoisting

equipment with sufficient lifting capacity to lift stator and rotor

simultaneously ， at first put the rotor into the stator to make rotor

smoothly lay on the inner surface of stator core ， and then lift the

stator．The stator and the rotor are together hoisted on the baseplate as

shown in Figure 3.In case the customer's hoisting equipment is insufficient to lift stator and rotor simultaneously, first lift the stator and lay it on the base plate and insert wooden blocks below the stator base to raise the

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stator (See figure 4 )，and then lift the rotor and lay it on the inner surface

of stator core smoothly. Then slowly lower them into place together to carry out installation as shown in Figure 4. Height to be raised for the stator will make the rotor not touch bearing pedestal when laying the rotor on the inner surface of the stator. But the installation method of raising

stator is unsafe ． In order to avoid accidents customer must be very

careful when using the method．

In Figure 4，B>A should be used for A and B dimensions.

Figure 3：Installation sketch of Figure 4：Installation sketch of

hoisting stator and rotor raising up stator and rotor together for short shaft with wooden block for stator

type motor shaft type motor

b．Long shaft type

For long-shaft type motor，if the lifting capacity of customer's hoisting

equipment is sufficient， the installation method of long-shaft type motor

can be the same as that of short - shaft type motor, i.e. stator and rotor

are lifted together and laid on the base plate to install ．If the capacity of

hoisting equipment is insufficient ，first lift the stator and lay it the base

plate by the side of shaft extension bearing ．(At the moment，take care

that the end part of stator coil should not touch the base plate.)Then，lift

the rotor and insert it into the stator obliquely．Properly move the stator a

little to make the rotor just lay on the inner surface of the stator core，and

then carry out installation work as shown in Figure 5.

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2.7.1.6 First fix the stator with dowel pin ，but do not mount bolts on

motor base plate temporarily ， and then adjust the rotor to make the

stator in alignment with the rotor core ． At last ， insert the lower half-

bearing into the bearing pedestal to make rotor be supported on the

bearing shoe．

At this moment ， take care that clearance between each shoulder

blade of bearing retainer and between two ends of the bearing bush

should be equal (Generally they are 2.5-3.0mm)，as shown in Figure 6.

Figure 5 Installation diagram of Figure 6 Axial clearance between long-shaft type motor bearing bush and rotating shaft

stator and rotor are

separately hoisted．

2.7.1.7 Measure the length of air gap

between stator and rotor in upper，lower,

left and right four locations at front andrear ends of the motor with measuring scaleby inserting it into air gap. All gap lengthsshould be evenly distributed and the absolutevalue of difference between the average valueand the maximum value or the minimum value Figure 7 Radial and axialshould not exceed 10% of the average value. Measuring with

Thus，it is agreed that air gap lengths are calibration scale

even practically ， in consideration of forming of oil film in the bearing

during motor running ， it would have influence on variation of air gap

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length． It is recommended that the upper air gap length may be greater

than lower air gap length with 0.10-0.15mm approximately during air gap calibrating.

2.7.1.8 For motor which is directly connected with elastic

couplings，concentricity of two half couplings，on the motor and its driven

machine as well as parallelism and clearance length of their end face can be measured with radial and axial two-purpose calibration scale as shown in Figure 7.Concentricity can be checked with the relative value of

clearance a ． and parallelism can be checked with the relative value of

clearance b．The checking method is as follows．

Take four points(0° 90° 180° 270° ) within one circumference ． If the

difference of measured value of a or value of b at these four points

mentioned above does not exceed 0.04-0.05 mm ， the result is

satisfactory．

The clearance between the end faces of two half couplings is determined by the sum of axial movements of the motor and its driven

machine ． As to the motor (i.e.the driven machine is excluded from

consideration) ， the clearance length should be at least 3 mm ． In case

gear coupling is used，please refer to the installation instructions relevant

to gear box which are provided by the mechanical department．

2.7.1.9 After the position of stator and rotor as well as air gap etc are

accurately adjusted, tighten anchor bolts immediately ． Assemble each

components of bearing part．Before final mounting of end cover，recheck

the air gap once．

2.7.1.10 As to oil-ring bearing ， fill the bearing with oil to the height

specified in the oil gauge ． As to oil pressure bearing and composite

bearings oil pipe system should be ready on advance ． Grease oil used

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should conform to the specification specified in the document attached to the machine.

2.7.1.11 Connect ground wire to the baseplate ． Carry out wire

connection of stator and rotor(wound-rotor motor) ． Cable head and

amour，etc．should be grounded．

2.7.2 Centering control2.7.2.1 General description

When the motor is placed on the base frame or base plate ，place it

near the final location of alignment as close as possible ． Set properly

spacers as mentioned above in the preliminary decision．

The rotor of motor with pedestal sliding bearing should be located at position of magnetic center or axial travelling middle position of the

rotor(mechanical center) ． If position of magnetic center can not be

determined or the marking of position of magnetic center is not

provided ， set the rotor at the mechanical center ． Under certain

condition，take care that there is a thermal expansion in the shaft of the

driven equipment ． Though the motor is located at the position of

magnetic center when installing under the room temperature ， the axial

position of motor rotor will displace under normal operation due to this expansion in order to ensure that under hot operation the motor rotor always situates at the position of magnetic center aligned, when installing motor under room temperature, the stator should be moved for a small distance in the direction away from the driven equipment. The value of distanceis equal to the length of expansion of the driven equipment shaft between mort temperature during installing and normal rated temperature. This value should be provided by the manufacturer of the driven equipment. This method can prevent motor bearing from damaging caused by the thrust load.

When positioning of motor has fulfilled the requirement of axial traveling ,mount and tighten the anchor bolts. Check the angle and position of the motor, to see whether or not it is aligned. Alighment of angle is verified by the method of measuring gap between faces of

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coupling with filter gauge at top, bottom and two sides of the coupling. All readings should be taken at the locations of the same radius which is calculated from shaft center. Size of radius taken is from the place where the radius is as large as possible. Then rotate the two shafts (motor and shafts of driven equipment) to 180° together. Again, measure at the positions of each 90°. So, to check the angle between shaft axes accurately can be ensured and it would not be influenced by projecting of any axial positions.

Attention: Though the elastic coupling permits a certain amount of out of alignment of shaft axis, but even if there is only several thousandths millimeter of out of alignment. It is possible that tremendous vibration would be introduced into the system. In order to obtain maximum service life and minimum vibration of bearing, align the center line of unit as accurately as possible and check the condition of alignment under hot status.

After recommended center position is finally adjusted, the dowel pin should be hammered into the base frame of base plate through the base. Thus it facilitates centering adjustment and reinstallation of the motor after it has been removed from the original position due to certain reasons.

2.7.2.2 The motor adopts magnetic centering adjustment of end-cap type slide bearing .After the motor is started independently and attained to stable condition ,measure the position of pointer ,checking whether it is the same as the marking on the pedestal .Then firmly fix the coupling and the shah. So, during motor running the magnetic center can be ensured in stable condition basically, to decrease various unfavorable influences to motor itself or to main motor due to excessive deviation of magnetic center.

1. Adjusting nut 2. Pointer 3. Marking

Figure 8 Adjustment of magnetic center2.7.3 For the positioning pin of pedestal bearing, the non - insulation

steel pin is used when delivering from factory. The user shall replace the insulation pin before operation to prevent shaft current happening (insulation pin is supplied when leaving from the factory).

Be sure that all installation and repair work have been accomplished. Inspect foundation anchor bolts and dowel pins to ensure installation in position and proper tightening.

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2.8 Electric measurement2.8.1 Measurement of insulation resistance2.8.1.1 When measuring insulation resistance of motor winding, it

should be carried out in actual cold state.2.8.1.2 Choice of megohmmeterAccording to rated voltage of the motor, choose the megohmmeter

from Table3. Table 3Rated voltage of motor ( V ) Specification of megohmmeter ( V )

Below 500 500500-3000 1000

Above 3000 2500When measuring insulation resistance of embedded temperature

detector, megohmmeter with voltage not higher than 250 V should be chosen.

2.8.1.3 Measuring methodIf the beginning and end terminal leads of different phase windings are

all led out from the motor case, the insulation resistance between each phase winding and the case as well as that between various phase windings should be measured separately, the three phase windings were already connected in the interior of motor and only three terminal leads were led out, insulation resistance between all windings and the motor case should be measured. As to wound - rotor motor, insulation resistances of stator winding and rotor winding should be measured separately.

After measuring, static charges in the winding should be discharged to ground.

2.8.1.4 Under hot condition, the insulation resistance of stator winding of motor shall not be lower than the value obtained from the following equation:

where: R--Insulation resistance of winding, MΩ U--Rated voltage of winding, V P--Rated power, kW2.8.2 Measurement of direct current resistance of winding under actual

cold condition2.8.2.1 Temperature measurement of winding under actual cold

condition. Place the motor in a room for a period of time, measure the temperature of end of motor winding or iron care with a thermometer (or embedded temperature detector). When difference between temperature measured and temperature of cooling medium does not exceed 2 K, the

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temperature measured is the temperature of winding under actual cold condition. In case the temperature of end of winding or iron core is unable to be measured, using temperature of motor case instead of temperature mentioned above is allowed. As to large- sized and medium-sized motors, time of placing thermometer should not be less than 15 min.

2.8.2.2 Measuring methoda. Measure d. c. resistance of winding with double - arm bridge or

single-arm bridge. When the resistance is equal to or less than 1Ω , the double- arm bridge must be adopted in measurement.

b. When automatic detecting device or digital micro- ohmmeter, etc instruments are used to measure the resistance, testing current passing through the winding to be measured should not exceed 10% of its normal operating current. The time of energizing should not exceed 1 min.

c. When measuring, the motor rotor is stationary and the resistance of stator winding should be measured at terminals of lead wire of the motor. As to wound rotor motor, the resistance of rotor winding should best be measured at the connecting piece which connects winding and collecting ring.

Each resistance is measured for 3 times. The difference between reading of each time and the average reading of three times should be within ±0.5% of the average reading. The average rea3ing is chosen as actual value of resistance.

d. If there are beginning and end terminal wires of each phase winding led out from the motor, the resistance of each phase winding shall be measured. If there are 3 wire terminals led out from the motor in which 3 phase windings are already connected internally, the resistance can be measured between any two wire terminals. The value of resistance of each phase (Ω) can be calculated according to the following equations:

For star winding connection: Ra= Rmed - Rbc (1) Rb= Rmed - Rca (2) Rc= Rmed - Rab (3)For delta connected winding:Ra = RbcRca / (Rmed - Rab) + Rab - Rmed (4)Rb = RcaRab / (Rmed - Rbc) + Rbc - Rmed (5)Rc = RabRbc / (Rmed - Rca) + Rca - Rmed (6)Where: Rab, Rbc and Rca are resistance values measured between

terminals of A and B, B and C and C and A separately, Ω If the difference between the resistance value at each line end and the

average value of these three line end resistance meets the stipulation shill be calculated according to following equations:

For star connected winding:

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(7)

For delta connected winding:

(8)

where: Rav - Average value of resistance for 3 line terminals. Ω3. Electric connection and start-up3.1 ConnectionThe control circuit, overload protection and grounding of the electric

motor shall be managed according to specifications. In order to protect the safety of personnel, there is a special grounding device on the base of the electric motor.

3.2 Initial start - up not connected with loadThe first time of energizing after the electric motor is newly installed,

overhauled or stopped running for a long period of time is deemed to be the initial start- up. It is suggested to carry out the initial start- up under the condition that the electric motor is not connected to the driven machine. Prior to the initial start - up, inspection of the following items must be carried out.

3.2.1 Confirm that all installation and maintenance work have been finished and inspected.

3.2.2 Confirm that all temporary supports and cover plates have been removed.

3.2.3 Inspect the bearings to ensure that all oil containers are filled with the correct lubricating oil to the proper level. If the forced lubricating system is adopted, it must be confirmed that the lubricating oil must be correct in trade mark, type and quality as well as that it is filled to the proper level. And, at the same time, the lubricating oil system is in the operating condition. For pressure and temperature of the incoming oil, refer to 4. 10. 2. 7

3.2.4 Measure the insulation resistance of winding. Dry the winding if necessary.

3.2.5 Check if the frequency, number of phases and voltage of the power source conform with the value on the nameplate of the electric motor and whether the voltage fluctuation is within the limit of 5% of the rated value on the nameplate.

3.2.6 Check the lead wire of the electric motor and the mark of the power supply line to determine if the direction of rotation of the electric motor is in accordance with the demanded direction.

3.2.7 Check whether there is proper space around the electric motor for air ventilation.

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3.2.8 Check whether all the air inlet and outlet ports of the electric motor are free.

3.2.9 Check whether dust in the electric motor has been removed. If compressed air is used to blow the electric motor, the air must he clean and dry while the pressure should not exceed 2*10 Pa (2kgf/cm2).

3.2.10 Check whether there are sufficient clearance between all moving and stationary components.

3.2.11 Check whether there are any foreign materials in the interior of and on the electric motor. If any, clean thoroughly.

3.2.12 Inspect while turning the electric motor and listen carefully whether there is noise of friction.

3.2.13 If there are current transformers on the electric motor, the secondary winding must be connected to the special- purpose control equipment or must be short - circuited. The electric motor shall never be started up under the condition while the secondary winding of the current transformer is in open circuit.

3.2.14 Check all the other electric connections to see whether they are proper.

3.2.15 Cheek the connections of the electric motor and the auxiliary equipment

3.2.16 According to the voltage and phase number of space heater shown in the overall diagram, confirm the power supply.

3.2.17 Push the rotor of the driven equipment m the direction toward the limit value of axial travelling gap of the rotor, confirm that the half coupling of the motor at the limit position would not touch the half coupling of the driven equipment. Special care must be taken that touch between the half couplings must be corrected before non- connecting start - up.

3.2.18 Cover plates being moved due to inspection should be replaced to the original places. Check and confirm that all cover plates, protective coven and filter, etc are properly set up.

3.2.19 Confirm that all protective devices and monitoring devices are properly connected and operated.

3.2.20 Check and confirm that the water and oil supplying systems (if any) have been connected and they are operating. Special attention should he paid to the Water, air- cooled motor. In the cooler, the residual gas must be discharged through the gas discharging valve and the electric motor must operates properly.

3.2.21 Connect the electric motor to power supply. Pressing the start up control button and then pressing the start control button immediately to check the direction of rotation of the electric motor. If the practical direction of rotation does not conform to the direction demanded for load and that specified for the electric motor, after the rotor stops gradually due to inertia, change the connection of the lead wire to correct the

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direction of rotation,3.2.22 Start the electric motor again and let it operate. Check the

temperature of the bearing frequently, especially within the preliminary 2 hours of operation. In this period, the rate of temperature rise of the bearing can better indicate the trouble than that of the absolute temperature of the hearing. The final temperature of the bearing shall not exceed 80℃ (for sliding bearing) and 95℃ (for rolling bearing).

3.2.23 When start up for idle running of the electric motor, the magnetic center must be properly adjusted and set a mark for it. Set up a flange and match it well with the flange of the main machine to guarantee that the motor operates in the magnetic center.

3.3 Preliminary start up-connection of load3.3.1 Remove all supports for positioning of coupling. Based upon the

instruction of the manufacturer of the coupling to lubricate and assemble the half coupling. Pay attention to the matching marks set by the coupling manufacturer. Assembling strictly according to the matching marks is very important.

3.3.2 Start up the electric motor according to the instruction attached to the control equipment of the motor.

3.3.3 If, after switching on for 1 -2 seconds, the electric motor cannot rotate, cut off the power supply immediately. The trouble my be caused by the following reasons:

a. Terminal voltage of the electric motor is too low.b. Resisting torque of the machinery to be driven by the electric motor

is too large.c. The rotation of loading machine is blocked.d. Electric connection is not complete.e. The combination of the above reasons.Analyse the causes in detail and take actual steps to remedy. After the

trouble is removed, restart up.3.3.4 If the electric motor cannot rotate at full speed (and it rotates at

a lower speed over 20 seconds, cut off the power supply immediately). The trouble may be caused by the following reasons:

a. Terminal voltage of the electric motor is too low.b. Under the condition of low creep rotating speed, the rotating torque

of the load is equal to the motor torque.c. The ramble may be a result caused by the combination of the above

reasons.Analyse the causes seriously and take actual steps to remedy. After the

trouble is removed restart up.3.3.5 Pay attention to the vibration the motor. The value of vibration at

this time may be different from that when the motor is not connected with driven equipment. If the vibration is too large after being connected, inspection is required for setting and it should be aligned to the center.

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Refer to the chapter for trouble shooting in this instruction book.3.4 Working system for start-upThe limiting range of the starting up working system shall not be

exceeded. Except the working system is defined on the nameplate, the working system defined below shall not be exceeded.

3.4.1 When the initial temperature of the motor is the ambient temperature it is permitted to start-up continuously twice. Between the two times of start- up, motor shall be stopped naturally.

3.4.2 When the initial temperature of the motor is the operating temperature of rated load, only one start - up is permitted.

Special attention: due to repeated start - up or the long time for start- up, the overheat and overstress would reduce rapidly the service life of the stator winding or the rotor.

3.5 Taking out of service3.5.1 On the work siteIf the motor stop to use over one month but is still connected to the

machinery driven on the foundation follow the stipulations listed here:a. Discharge the oil and replace it with clean anti- rust oil (For rolling

bearing with lubricating grease, this provision is not applicable.) Every month the shaft should be turned for several times, if the environment is damp and dewing may be formed, then the time interval should be shorter.

b. Energize the space heater and check periodically to guarantee it is under good working condition. If there is no space heater on the electric motor, several electric bulbs of 100W or 150W may be set in the electric motor and then they are energized to keep the interior temperature higher than that of the exterior.

c. All bare metallic surfaces exposed in the open air must be coated with antirust oil.

d. Prior to restart up the electric motor, clear away the anti- rusting coating on the surface. Discharge the remained oil and rep, Lane it with dean working oil to the level specified. Remove all temporary heating devices set in the interior of the motor and cheek the inspection items concerning prior initial starting up in provision 3. 2.

3.5.2 Storage of the electric motor at the place away from the working site If the electric motor is transported and set at a place away from the working site over 1 month, recommend the following stipulations are to be followed.

a. All metallic bare surfaces exposed are to be coated with anti- rust oil.

b. Mount the original fixing device of the rotor and clamp the rotor tightly when handling it by crane, to avoid impact.

As to the motor that possesses shaft insulation requirement, the insulating pins should be replaced with metallic pins. When operating,

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don't forget to change them with the original insulation pins.c. Store electric motor in the way mentioned in provision 2. 2.d. Restart-up the electric motor according to specifications in

provisions 3.2 and 3. 3.4. Inspection and maintenance4.1 In order to guarantee that the electric motor can operate

continuously, safely and reliably, the program for repair and maintenance should be worked out according to the following criteria. Hidden troubles must, be found out and the occurrence of trouble must be avoided.

4.2 Routine inspection of the motor during operationThe lubricating system should be inspected frequently. Oil level of all

oil gauges must be checked. Through the observation window of the oil ring watch the rotation condition of the oil ring. If oil leakage is found, search the causes and correct them. Supervise the colour change and contamination of the lubricating oil. Pay attention to serious noise or serious vibration or sudden increase of them. They should be remedied as soon as possible. During the continuous operation, check the temperature of beatings periodically.

4.3 Maintenance planUnder general conditions of application, the following plans for

maintenance are recommended. (Different enterprises, may work out their own plans according to practical conditions)

4.3.1 Weekly inspectiona. Measure the temperature with the measuring temperature devices.

Measure the temperatures of the stator winding, cooling air and bearings. (For example, buried type resistance temperature measuring element may be used.)

b. Listen carefully whether there is abnormal mechanical noise or other changed noise, in the motor. (Such as friction or tapping sound, etc.)

c. When there is water - air heat exchanger, check the water pipe to see if it leaks.

d. When a filter device is used, check the filter and see how seriously it is contaminated.

e. Measure the temperatures of bearings at the location where the temperature measuring device is set and record them.

4.3.2 Monthly inspectiona. Measure vibration of the motor with the instrument. The measuring

point is the middle of the bearing cell.b. Check all electric cables, connecting wires and their fastened

degree.c. If it is a wound rotor, check the collecting ring, conducting bolt and

the electric brush to see whether there is dust deposited. When it is a needed dear away the dust. Cheek galling of the electric brush and whether the brush can move freely in the brush- holder. In case of need

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change a new electric brush.d. When this is a filter, after the action of filter monitor device (such as

the pressure difference switch), the filter should be replaced or cleaned.e. In the bearings with oil lubrication, check the movement of oil rings

to see whether the movement is smooth as well as the condition of oil carrying. Check the sealing of bearing to see if oil leaks out. If contamination by oil occurs, clear away the dirts and inspect the equipment for oil supply.

4.3.3 Quarterly inspectiona. Measure the insulation resistance of stator winding and rotor

winding.b. A megohmmeter with rated voltage off 500V is used to measure the

insulation resistance between the insulating bearing or bearing seat and the steel base.

c. Check the degree of dust deposited in the electric motor.d. Check the degree of dust deposited in the power supply on the

instruments and on the control connecting wires.e. Check the grounded electric brush (if any), ensure pressure on the

electric brush.4.4 Periodic inspectionBased upon the actual service condition inspect the electric motor

every half year or every year. The following items are to be checked every half year.

4.4.1 If the following conditions exist in the surrounding environment of the electric motor.

a. Corrosive or conductive dust.b. Cotton liter (or very dirty environment exists while using the electric

motor)c. Chemical fog steam, salty mist or oily mistd. moist or very dry: radiating heat, animal disturbance or substances

which cause the growth of mould exist in the atmosphere.e. Abnormal impact, vibration or external mechanical loading4.4.2 If the electric motor operates in the following circumstances:a. Deviation from the rated voltage and (or) frequency is too great.b. Poor air ventilation of the room or temperature of air in the

environment is in excess of 40℃.c. The motor bears loading of twisting impact, repeated over loading or

acceleration for a long period of time is caused due to large load inertia.4.4.3 Inspection list should be prepared according to the following

requirements to guarantee proper operation of the motor.a. Clean bearing throughly and replace the lubricating oil (grease). If

abnormalities were found with the bearing, inspect the bearing.b. Take actual steps to remedy oil leaking at the bearing sealing.c. Remove the end cover and the top housing. Check whether

22

condensed dew or water deposit or rusting of iron exists.d. Pay attention to dust or other foreign materials deposited.e. Check component part, especially to check whether over heating

occurs to the insulation. The phenomena are air bubble, change of colour and carbonization to be taken place. Check all insulated electric joints to see whether there are galling of insulation, breaking of paint and shifting of coils. Measure stator winding insulation resistance.

f. Check all joints to see whether there are phenomena of improper connection or overheating, flying arc, corrosion, etc. Based on requirements, take actual step to remedy.

g. Check all bolts and nuts to see whether they are well fastened. Special attention must he paid to the fasteners on the rotor, because they are loose they may fall into the motor.

h. Check if there is overheating or electric corrosion of the main lead wire.

4.5 Inspection and clearing up of windingRemove the end cover or wind shield (if any) to facilitate the

inspection. In order to inspect thoroughly and to clear up the winding, the rotor must be pulled out from the stator.

4.5.1 Dry cleaningWhen the surface to be cleaned is easy to approach and there is only

dry dust on it, just wipe it with a piece of clean cloth without linter. A satisfactory result can be obtained, no “flannel” can be used, since the linter may stick on the insulation surface and would cause deposit of dust. Such villus is harmful to insulation especially of high voltage electric motor.

4.5.2 Brushing and suckingThe dust can be removed with short and hard hair brush. Then dean

with vacuum cleaner for sucking. (No metallic brush is permitted to use). To avoid the dust from spreading over or depositing on other equipments.

4.5.3 Blowing or sprayingBlow or spray air to the very narrow space where it is almost

impossible to approach. (The electric motor must not be moistened). Direction of air blowing must not bring the dust into the deep interior of the electric motor. This is because it is hard to clear away the dust there and at the same time the dust might block the air ventilation channel.

Special attention: Pressure of air used shoed not be higher than 2*l05

Pa(2kgf/cm2). The air must be dry, free from condensed water from the air pipe.

4.5.4 Cleaning with solventSolvent is very effective in cleaning asphalt, grease, wax on the

electric equipment.To clean insulation articles, inorganic volatile solvents or solvent of

petroleum are adopted. In places where there is risk of fire disaster, clean

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with solvent which has the effect of inhibition.Special attention: When cleaning with solvent, the ventilation must be

provided to prevent fire disaster, explosion and damage to human health.4.6 Insulation resistanceEven if the insulation resistance of winding does not reach at the

lowest value, drying the electric motor is required and according to demand, the motor must be cleaned.

4.6.1 Measurement of insulation resistanceRefer to 2.8.1 for measurement of insulation resistance.4.6.2 Drying the electric motorIf the insulation resistance is lower than the permissible value, after

being cleaned, dry the electric motor with one of the following methods.4.6.3 The following are several ways to dry the electric motor when it

is installed on the working site.4.6.3.1 Copper - loss heating methodWiring diagrams of the copper- loss heating method are shown in

Figure 9 and Figure 10.

Figure 9 Wiring diagram of the Figure 10 Wiring diagram of thecopper- loss heating method copper- loss heating method

with current passing through stator with current passing through rotor.In Figure 9, the rotor of electric motor is blocked. The stator winding is

connected as it is in working state. For the electric motor with wound rotor, the rotor winding should be short - circuited. Then, apply 10-15% of rated voltage to the stator winding (according to proper connection, alternative voltage of 3 phase power frequency is used). Thus, the current of stator reaches 50-70% of the rated value. So, the electric motor becomes hot due to copper-loss. In order to avoid damage of the brush on the wound rotor, user it better not to conduct the 3 lead wires through the brush. It is proper to short - connect the rotor winding on the 3 lead wires of the rotor or on the electric conducting rod of the collective ring.

In Figure 10 the wiring is only applicable to the motor with wound rotor. The principle is same with that shown in Figure 11. The only difference is that the voltage is applied to rotor in stationary state and the stator winding is short circuited. Not that the voltage of the incoming line shall be about 10 - 15% of the rated voltage of the rotor. At this time, the current of stator will reach 50 -70% of the rated current of the stator.

The above mentioned copper loss heating method is suitable for motor which is already assembled. If the stator is treated separately, the voltage

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applied should be lower.4.6.3.2 Blast drying methodSketch of hot blast drying is shown in Figure 11. The air and hot air

(70-95℃) is blowed in to the motor.The power of air- heater is: 0.4pN/100 + 20 (kw) PN is the rated power (kw) of the motor to be dried.

Figure 11 Hot blast drying methodIf the motor is dried together with the rotor, during the drying process,

the rotor must be turned 180°periodically, to avoid deformation of the rotor in beating for a long period of time. Change the position of blasting periodically, so various parts of the coil may be blasted evenly.

The time required to dry the motor relates to the moisture contained in winding, the temperature of heating, etc. The time period varies from over 10 hours to several days and nights (round the clock). During the beginning period of drying, the insulation resistance would drop temporarily and would rise again later. Finally, it comes to a steady value. If the steady value is kept for 3 - 6 hours without any change, the drying treatment can be ended.

1. winding temperature (℃) 2. insulation resistance (MΩ) 3. temperature 4. resistance (insulation) 5. time period for drying (hour) Figure 12 Typical curve of insulation resistance and winding temperature versus time.In the process of drying, record insulation resistance, winding and

ambient temperatures. When the methods of iron- loss and copper- loss drying are adopted, the voltage, current, etc should be recorded, too. A diagram showing the curve of insulation resistance and winding temperature versus time must be drawn as showing in Figure 12.

The time interval far recording between the measurements is half an hour at the beginning while the insulation resistance becomes steady, it is an hour.

When current is used for drying, the motor shall be grounded for safety.

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During the drying period, the temperatures of various parts of the motor shall not exceed the data listed in Table 4.

Table 4location for

measurementmethod of

measurementmax.

temperature ℃Winding and iron coreWinding - ditto-Temperature of airduring hot blast drying

ThermometerResistance methodTemperature detector- ditto -

709080-8595

4.7 Disassembly of the motorEvery step in disassembly of the motor shall be recorded in sequence

to serve as reference in reassembly. The following shows general procedures used.

4.7.1 Cut off all cables and lead wires connecting with power supply instruments, monitor devices and grounding devices.

4.7.2 For the motor with sliding bearings, discharge oil in 2 bearings. If there is another oil supply system for the bearing, shut off the oil pipeline.

4.7.3 Remove the complete top covering device (if any).4.7.4 Remove cover plate, guard board shutter or pipeline.4.7.5 Remove the anchor bolts and positioning pins of the motor and

disengage the connecting shafts. 4.7.6 Remove the coupling from the shaft extension. If there are

couplings at the shaft extensions on the two ends of the motor, they should be all removed.

4.7.7 Remove all bearing covers and temperature relays, thermocouples, etc around all the bearings. Then remove the upper half of bearing box (refer to sliding bearing) or bearing sleeve (refer to rolling bearing)

4.7.8 For the wound rotor, remove the lead wire between the collective ring and the rotor connecting - wire box. Remove away the brush from the brush holder. For the motor with collector ring attached, the collective ring and the cover seat must be removed, too.

4.7.9 Remove the bolts from the end cover and then remove the end cover with the help of the hole for bolt, use the bolts for lifting and take away the two end covers.

4.7.10 With the help of a special tool , remove the fastening retainer from the shaft, then remove the rolling bearing.

4.7.11 In the motor with sliding bearings. Remove the pins and bolts from the bearing bush first. Screw in the bolts for lifting and lift away the upper half of bush. Then remove the oil ring. At the two ends of the rotor, simultaneously raise it to the position which makes the lower half of bush to be free from loading. With help of the hole for bolts on the lower half of

26

bush, set the lower ball of bush to the top position and lift it away. Remove the bolts at the lower half of bearing housing and remove the lower half of bearing housing from the sealing place of the end cover.

4.7.12 Insert hard paper board or plywood into the internal hole of the stator and set the rotor in the internal hole of the stator.

4.7.13 Remove the internal sealing ring and other devices from the shaft.

4.7.14 Lift carefully the stator assembly (the rotor is left in the stator) and remove it away from the base. Set it on the place where is easy for storage or for work.

4.7.15 Remove the fan and the wind shield etc before pulling out the rotor from the stator.

4.7.16 When drawing the rotor out of the stator, be sure there is sufficient space around the stator and rotor, in curler to pull out the rotor. Wrap well the neck of shaft to avoid the journal to be damaged.

4.7.16.1 On the rotor end where there is no coupling mount a steel pipe with proper internal diameter, length and strength. Do not set the steel pipe at the extensions of shaft, or set a red copper ring with proper diameter in the steel pipe as a liner to protect the diameter of shaft from being damaged.

4.7.16.2 Tie the lifting cable on the steel pipe and on the place at the shaft near the coupling.

4.7.16.3 Lift carefully the rotor to the center place near the air gap. Gradually move the rotor to the end of the coupling and trail it away axially from the stator, or under special conditions, pull it out toward the end without coupling. Pay attention not to drop the rotor or special care must be taken to avoid it to scratch the internal bole of the stator and the winding of the stator. When the rotor is pulled out of the motor base, it must be seated on a reliable support.

4.7.16.4 Remove the steel pipe and the lifting cable. Beware not to hurt the stator winding.

4.7.16.5 After the rotor is pulled out from the internal hole of the stator, it should be placed on the working site easily to approach and a board or other suitable material must be put under it. After the rotor is well placed, inspection and repair and maintenance can be caned out.

4.8 Clean the motorClean out dust, grease, carbon powder, metallic powder, and oxides

away from the motor. It is best to use the vacuum cleaner to clean the dirts. There should be a nonmetallic sucking tip on the cleaner.

4.9 Reassembly of electric motorThe motor is to be reassembled according to the reversed sequence of

disassembly. Fasten all internal bolts and fit properly new locking elements.

4.10 Maintenance of bearing

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4.10.1 Rolling bearingLubricating grease applied to the bearing or change of its brand should

conform to specifications of the drawings and documents related.The rolling bearings are replaceable standardized elements.For the motor with rolling bearing which is lubricated with grease, after

working for about 2,000 hours, the old grease must be replaced with new one. If the bearing is used in dusty and moist environment, the lubricating grease should be replaced more frequently.

Prior to start up the motor which has been kept in store for a long period of time, the lubrication of rolling bearing must be inspected first of all. In case the original lubricating grease is already hardened or contaminated, the bearing must be cleaned with kerosene first and then cleaned with gasoline. Then, clean lubricating grease is poured into the oil groove. The quantity is about 2/3 of the volume capacity. If the quantity of grease is too much, the bearing would become overheated during working and cause decomposition of the grease. Oh the bearing there are inlet and outlet oil pipes, oil indicator and oil discharging pan. So, oil filling and draining can carry on without stoping the motor. Inspect carefully the device for oil inlet and outlet to see whether the oil passages are unobstructed and smooth to guarantee safe operation of the bearing.

In large power motor, the double bearing of bearing is used. The structureis shown in Fig. 13. During assembling after inspection and repairing, the spring in the inner cover of the bearing should be set in the groove of the inner cover with lubricating Fig.13 Structure ofgrease for bearing. It may be used to set rolling doublethe spring in the groove. Bearing

Then, set the inner cover of the bearing. Pay attention to keep the spring in the groove to ensure the bearing to operate safely.

4.10.2 SlidingThe sliding bearing used in the horizontal type motor may be end

cover bearing or pedestal bearing.On the shaft extension of the motor with sliding bearing, external

applied axial force and radial force except the weight of the coupling are not permitted to bear.

4.10.2.1 Insulation bearingIn order to avoid the electric corrosion damage of bearing shoe due to

shaft current, bearing insulation is set.Insulation method adopted for bearing varies with the structural types

of the bearing. On the horizontal type motor with end cover bearing, for bearing insulation, the insulation layer is stuck on the ball- shaped shell of the bearing seat and supports the bush. When removing the bearing horn

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the ball-shaped shell with the insulation layer, special care must be taken to avoid damaging the insulation layer. For the horizontal type motor with pedestal bearing, the insulation is realized by adding insulation gasket between the bearing seat and the base plate of the motor.

In assembling and disassembling, be careful not to hurt the insulation.In periodical inspection for the motor or for any other purposes, when

the motor has been disassembled prior to operate again, before starting-up, the insulation of the motor must be checked.

4.10.2.2 Oil replacementOil replacement depends upon essentially the operating time, the

times for assembling, the operating temperature and degree of contamination of oil. When the oil is seriously contaminated or its temperature rises suddenly which is not affected by external influence, the oil must also be replaced.

Motor with self- lubricating bearing (or motor with pressure lubricating bearing) should often be inspected whether the bearing works properly. For the lubricating oil, if there is obvious change of colour which is a sign of deterioration, change with new oil in time. For self - lubricating motor, note the oil level in oil box.

When the level is lowered, replenish with new oil.After operating for 4,000 hours under normal condition, oil in the self-

lubricating sliding bearing should be replaced. (The motor must be stopped when replacement takes place.) This specification is based on the consideration of aging of the oil. Even if the motor is always in unoperating - state (such as stand by motor in generating set for emergency putting into use or motor not used), replacement of oil is necessary, too.

Sliding bearing with oil supplied by pressure, the replacement of oil is 20,000 hours after operation.

For high speed motor, time interval of replacements of oil should be reduced.

4.10.2.3 Galling of partsInspection of bearing according to plan is necessary, since galling of

bearing can be found in time and thus they can be replaced in time.In normal operation of motor, the temperature of bush should not

exceed 80℃.Within the preliminary running period of 2 hours, measure the temperature of bearing is important. If the temperature of bearing exceeds the specified value, stop running immediately and find out the cause.

If oil leakage is found ha the periodical inspection, check the dimensions of the sealing parts of the bearing and replace them ha time. In case abnormal running of oil ring in the horizontal motor is found in the periodical inspection, check the dimensions and pay attention to deformation.

The permissible diameter out - of - roundness of oil ring is shown ha Table 5

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Table 5

Internal diameter of oil ring (mm)Average value of any two measuringpoints apart with 90mm

(mm)

＞140-200

＞200-280

＞280-400

＞400-500

＞500-600

0.50.60.70.80.9

When serious fluctuation of beating temperature occurs or a sudden change of the temperature occurs, check if oil replacement for the bearing is required. Devices for monitoring beating temperature may be equipped. If there is no such devices, when abnormality is found in the temperature higher than that specified, measure precisely with a thermometer.

4.10.2.4 Periodically inspect clearance of the bush. Equal clearances shall be kept between each shoulder blade of bearing retainer and the two ends of the bush.

(Table 6 shows the radial clearance of bearing. )Table 6

Diameter ofbearing (mm)

Rotation speed

＜1000r/main

Max.clearance(mm)

Rotation speed

＞ 1000r/main

Max.clearance(mm)

80-120120-180180-250250-360360-500

0.08-0.160.10-0.1950.12-0.2250.14-0.250.16-0.30

0.160.200.240.260.30

0.12-0.210.15-0.25

0.18-0.2650.21-0.340.24-0.41

0.180.220.300.400.45

4.10.2.5 For motor with composite bearing, during operation the bearing oil level should be kept at the height specified on the oil indicator.

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This height is determined under the condition when the motor is stationary and the oil in oil pipe flows smoothly. The pressure of oil supplied by the oil pump at this time is to be set as the rated data. However, oil quantity under this rated oil pressure may cuase the oil level change in the bearing when the motor operates. The phenomenon are very obvious when the speed of rotation is high. Bearing with oil ring lubrication may have the same phenomenon. At this time, user should not increase the oil pressure (for composite bearing) or add more oil (for oil ring type bearing), otherwise, oil leakage will appear.

4.10.2.6 For sealing of end - cover bearing, the oil sealing device on the bearing cover is made of insulating material in the form of floating labyrinth which increases the ability of the bearing to resist oil leakage. In operation, the sealing ring and the rotating shaft are concentric. In order to ensure that no oil leakage of the bearing would occur in operation, inspection of sealing ring is essential. Note whether there is galling, scratching or burnt of the sealing ring.

4.10.2.7 Application and maintenanceDischarge residual oil in the bearing housing and dean it with

kerosene. Remove the deposits and dean thoroughly the detergent left in it.

For inspection of bearing insulation, in the case of the shaft of the motor is not contact with bearing measure insulation of pedestal bearing or end cover sliding hearing with a 500v megohmmeter. Disassemble the motor, the insulation resistance between the insulation gasket and the bearing seat can be detected. If the insulation resistance of insulation bearing to ground should not be smaller than 0.5mΩ.It indicates that there is no phenomenon of short circuit in the insulation resistance of the bearing. If short circuit happens in bearing insulation, find out the cause and remedy it.

Matching of the floating labyrinth in the sealing cover is checked. The floating labyrinth must be properly matched, it must not restrict the sealing ring from free radial floating. If necessary, deburr may be required. After accomplishment of various inspection and assembling work, pour in new lubricating oil to the serf- lubricating beating (including compound lubricating bearing).(the type & brand of the new lubricating oil is determined according to the type of motor). While pouting the oil, observe the oil level indicated at one side of the bearing housing. Look at the indication from the middle position of the observation window, correct oil level can be obtained. (mark it.) For bearing with pressurized oil supply to lubricate (including compound lubricating bearing), careful inspection of the joint of inlet and outlet oil pipeline is essential. Prior to starting- up the motor, note the bearing which adopts any kind of lubrication must have a little lubricating oil added in from the observation window which locates on the top of the bearing seat.

31

In operation, pay attention to the lubrication of beating. For bearing with oil ring to be lubricated, the smooth rotation of the oil ring should be inspected and observed frequently. For bearing with pressurized oil supply to lubricate (including compound type lubricating bearing) the pressure for oil supply shall not exceed 0.05MPa. If the supply pressure is greater than 0.1MPa, the user of the motor must install pressure reducing valve on the pipeline for incoming oil to the bearing. Temperature range of the incoming oil is 15℃ to 40℃.

The correct rotation of the oil ring shall be noted. Proper operation of the oil ring is uniform and silent. If the oil ring operates too slowly, the lubricating effect would be influenced while it is too fast and if slight noise is heard, it indicates that oil is insufficient.

4.10.2.8 InspectionInspect the bearing to ensure that no foreign matters exist in it. Clear

away any hard grains inserting in the bearing bush alloy and get rid of them. Wipe the bearing with a piece of cloth free from any pile. It has been dipped in clean oil. Check the two alloy surfaces of the upper and lower bushes to see whether there is anything wrong. The scratch on the surface of the upper bush is caused usually by unalignment of axes.

Note the trace of galling of bearings or damage of alloy of bush. Generally such phenomena are resulted from unalignment of center or vibration or both of them which cause over- load of the bearing.

If the galling is not very serious, grind off the projecting point produced by displacement of the alloy to make up the damaged location.

Note the trace of scratch on the surface of the lower half bush. The typical trace usually is in the shape of a belt with uniform width which radially extends to the full length of the lower half bush and it concentrates on the surface of bush at the bottom. If the trace is in the shape of belt with different widths, maybe it is due to inproper assembly of bearing or due to bending of the shaft. The trace of scratch that separates in a round shape on the surface of bush that may be caused by the granules on the exterior passing through the oil film or by the scratch on the surface of the journal of shaft. Common surface roughness may be due to abrasive dust in the oil. Check the surface of shaft journal to see whether there is projecting sharp spine. If there is spine, eliminate it and grind the surface.

Check surface of bearing to see whether there are recess points caused by shaft electric current. If such points are rotund, find out the reason of short circuit of bearing insulation and correct it. Open the stopper at the bottom of the bearing housing and discharge oil from the oil housing. Rinse the oil housing with clean oil or kerosene. Replace the stopper with sealing gasket to is original place. Check the internal diameter and side of the oil ring to see whether there are scratched marks. Any raised burr should be eliminated carefully with fine file. If the

32

result of filing is not satisfactory or the bearing should be changed refer to the instruction relating to it in this booklet. Clean thoroughly dust, grease, old sealing material from all sealing parts. Check all sealing parts to see whether scratches, raised burrs, galling, crack or other marks of damage exist. Remove or eliminate them with abrasive or sand paper. Replace the parts which are seriously damaged. Check if the matching of the float labyrinth with the sealing cover is proper, it should not get stuck. This sealing must he able to float radially freely. If necessary, deburr is required.

4.10.2.9 Points of attention when changing bearingChecking of the new bearing or bearing which is redeposited with the

alloy, matched with the neck of shaft is very important. The following procedures should be followed.

a. Check the neck of shaft to see whether there are projecting tips or sharp cutting marks or scratches. Use fine abrasives carefully to remove any projecting points or sharp edges. Inspect whether the repair work is satisfactory. Grinding or abrasion can trim the inproper alloy at the bush. Note the soft alloy around the bright spot which appearing on the welded surface of bush during assembly should be removed or eliminated.

b. Check the inner circumference of the bearing of the lower half bush of the new bearing. There should be no sharp cut. If necessary, slight scraping is permitted to make the surface smooth. However, don't scrape too much and enlarge the release area.

c. Wipe the lower half shaft bush according to provision 4.7.12 to slit it into the seat of bush. Attention should be paid to that in certain bearings with pressurized oil lubrication. The oil supplying groove should be faring the outer side of the bearing housing.

Special attention: When the lower half bush is slided into the seat, take care not to put your hand or finger on the position where the bush would enter to avoid being hurt.

d. Check the alignment to see whether it is proper and lower the jack, rotation shaft or support, set the shaft neck on the lower haft bearing. Turn the shaft to rotate for 3 revolutions in the regular direction. Raise the shaft and turn out the lower half shaft bush carefully. Observe the diagram composed of the projecting points expressed by the bright location. The portion contacting with shaft neck should contain 75% of the bright belt. If this is not reached, scrape out slightly the projecting points to change the shape of the diagram. Then reassemble it into the lower half bush and repeat the process of rotating the shaft. Disassemble and grind and lap the lower half bush until the desirable diagram is obtained.

4.11 The wound rotor asynchronous electric motor with fixed brush (normal contact)

The collective ring is the link connecting rotor winding and the brush to conduct current. The asynchronous electric motor with fixed brush is

33

equipped with collective ring made of steel or bronze. In the preliminary period of operation, the motor runs in no- load state for several hours. In this period of time wearing of the brush is quite serious. Due to a layer of carbon powder is on the surface, a current leakage channel is formed. The danger of flying arc is increased. In order to avoid damage to the motor, when delivering to operation, the following work must be done.

4.11.1 Record the length of the brushAfter about 10 hours of operation, measure and record the full length

of each brush alter wearing.4.11.2 Determine wearing of the brushMeasure the length of the brush every 80 hours and calculate the

wearing amount. Starting from the first measurement, calculate the wearing amount. When the wearing amount of a certain brush reaches 4 - 5mm, the carbon powder on the insulation of collective ring and slipping and on the brush device must be cleaned off. When the amount of wearing reduces, the time interval may he increased to 60 hours. But whenever wearing of brush is 4 - 5mm, the carbon powder must be cleared off once.

4.11.3 Conditions for normal operationWhen the wearing is smaller than 6mm/1000hours, it is considered

that the wearing of the brush is normal. Then, the brush device is repaired according to the plan of maintenance.

4.11.4 Cleaning work of the brush deviceEvery time when replacing the brush, the brush holder, insulation of

supporting screw, insulation between rings and belt of conducting rod must be cleaned. Every month the brush device and parts of sliding ring must he checked for the condition of dust deposition. Every 3 months, they Should be cleaned once. Never wash the brush device with solvent. The brush, brush holder and collective ring are best cleaned with the vacuum cleaner to clear off the carbon powder. Then blow with compressed air and wipe with clean dry cloth which is a small piece and must be changed often. This is the way to ensure that the carbon powder is thoroughly removed. In application on the surface of the collective ring, a layer of oxidized film containing graphite is formed.

Do not proceed unnecessary polishing since it can damage the oxidized film. Even during the time to replace the brush, this point must be kept in mind. Only when deposit of oil and carbon powder is stuck together, petroleum solvent may be used for wiping. At this time, all brushes must be removed. After cleaning, the brush device is cleaned by blowing compressed air and then wiped with clean dry cloth which is free from oil. After about 24 hours, replace the brushes in their original handles.

4.12 Cleaning of the coolerIn order to ensure proper running of the motor, inspect periodically the

empty cooler and clean the dust in it in time.

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The following is the cooler condition.The following methods can be used to clean water cooler.Reverse rinsing the coolerThis method is to reverse the direction of water flow of the cooler. Add

water from the water outlet to rinse the interior of cooler so that dirts or sand or mud deposit in the inlet comers can be rinsed out.

Rinse the cooler periodically.The interior and exterior of the cooler must be rinsed. The front and

rear water tanks can be opened to rinse with water.Leakage caused by corrosion and friction of dirts in cooler must be

remedied. The damaged positions are located usually in the expansion joints between the heat radiating pipe and the wall plates on the two ends. There are two ways to repair.

a. Press the hard plastic tube in cooling pipe with the method of stationary fit from the end of the wall plate to enclose the damaged position as shown in Fig.14. (In order to obtain better result, the wall, at the plastic tube to be pressed in, is coated with sealing compound fluid sealant).

1.Expansion jointsb. Block the cooling pipe which is damaged

so that water cannot pass through it. Generally,under the condition of blocking of 5% of the cooling pipe, the capability of heat radiation Fig.14 Repair of cooling pipewill not be influenced.

5. Accessories5.1 HeaterIf the heater is mounted on the motor, it is generally mounted under

the frame of the motor. The components of the heater are replaceable. When the motor is stopped for repairing, cut off the power supply of the heater at first, and then persons can be allowed to access the wiring area of the heater. During normal motor stoppage period, the heater can be connected to the power supply with the manual operation or the automatic control.

5.1.1 Replacement of heaterBefore the replacement of the burned heater, switch off the

corresponding switches and circuit breakers to cut off all power supplies of the motor. Stick on labels on these control equipments to prevent misoperating from switching on. The procedure of replacement of the heater is as follows.

5.1.1.1 Remove the side cover plate or the hood plate.5.1.1.2 Disconnect lead wire at outgoing wire terminal of the heater.5.1.1.3 Remove fixed bolts of the heater.5.1.1.4 Replace new heater on the place of original heater. Refit fixed

bolts on the heater.

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5.1.1.5 Reconnect the lead wires on the outgoing terminal of the heater.

5.2 Temperature measuring elementsWhen the temperature measuring dement is mounted, it is Pt100 or

Cu50Generally. If special requirements exist, it shall be implemented as per

the agreement.5.2.1 Stator temperature measuring elementIf the temperature measuring element is mounted on the motor, it

shall be normally mounted between the upper layer stator winding and the lower layer stator winding for monitoring the stator winding temperature. Six temperature measuring elements are mounted on the three symmetrical locations of the stator slot, each phase with two temperature measuring elements, one of them is standby, each temperature measuring element can provide two or three leading wire. Three lead- wire type temperature measuring elements can be used to compensate the influence of the lead wires of temperature measuring elements to the thermometer readings.

5.2.2 Temperature measuring element for bearingTemperature measuring element for bearing can be applicable to the

monitoring of the bearing temperature.5.3 Impulse wave protection deviceImpulse wave protection device is installed according to the technical

requirements of the customer. It can consist of the current transformer, lightening arrestor and impulse condenser. These devices can be mounted on the motor or placed individually and can be connected to the electric circuit conveniently. Thus they realize the protection to the motor to prevent switch from faulting operation or lines from lightning impulse. Inspect periodically the operating condition of these devices according to the relevant technical requirement.

6. Trouble shootingTo identify abnormal operating signs as early as possible and to take

remedy measures quickly are very important. Its meaning is to avoid a small fault becoming a serious fault later.

The following guide for trouble shooting may be helpful to find out and repair the trouble which may exist. If a trouble is found out, switch off the power supply of the motor at first.

The following is the brief description of problems which may be encountered, the possible causes and methods of treatment.

6.1 Motor cannot start upStarting trouble (see Table 7)Table 7

Trouble Possible causes Method of treatment

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The motor

can not start

up completely

At least there is one lead wire

of power supply in open circuit

state

Check the fuses the lines of power

supply and the lead terminal

No voltage Check the incoming line of power

supply

There is AC

sound from

the motor but

it cannot start

up

Open circuit in one phase in the

stator or the rotor

Check the incoming line of power

supply and repair the circuit

trouble

The motor

can not start

up with load

but it

generates

normal

magnetic

noise

Torque of load is too large Repair the trouble of drive with

load and inspect no load operating

condition

Load GD2 too large Incorrect type selection

Voltage of power supply is too

low

Measure the voltage of power

supply

Open circuit in the rotor

(in case of wound rotor )

Inspect rotor circuit (starter and

connecting wire)

The motor is

in no load

running but

cannot carry

load

After starting, one incoming

line of power supply breaks

Inspect incoming line of power

supply

6.2 Heat generation in bearingTrouble of heat generation in bearing (See Table 8)Table 8

Trouble Possible causes Method of treatmentOverheating of bearing

Unsuitable lubricant Refer to the grease or oil recommended in the assembly drawing or outline drawing

Improper oil level Check oil levelOil ring does not rotate

Check the roughness of oil ring and whether the guide oil slot is aligned with the oil ring

load too large Check the alignment of shaft axis and whether there is axial thrust load.Check if the shaft bends

Bearing surface is rough, bearing in clines and shaft neck pressure is excessive

Check whether the position of bearing alloy is displaced, and whether there is notch point caused by the axial current and corrosion.If there is notch point, inspect bearing

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insulation, scrape off or rematch the bearing and adjust the clearance of bearing bush. Polish shaft neck, if necessary.

6.3 Oil leakageTroubles of oil leakage (see Table 9)Table 9

Trouble Possible causes method of treatmentOil leaking Clearance between

sealing surfaces is too large

Check whether there is leakage of oil between sealing clearances

Ventilating hole of the breather is blocked

Check whether there is obstacle in ventilating hole

Grade and type of oil are incorrect

Check the oil to see whether it conforms to the specifications specified in outline drawing

6.4 Vibration and noiseTroubles of vibration and noise (See Table 10)Table 10

Trouble Possible causes Method of treatmentVibration and noise

Unbalance of the rotor

Disconnect the motor with load and then cheek and treat it

Unfixing installation or bad foundation

Retighten bolts, check spacers and reinforce the fixation of installation

Friction between machine parts

Determine the location of friction and then eliminate the friction

Breakage of squirrel - cage bar in the rotor

The amplitude varies with time. Most of these troubles occur in operation under load. Repair the rotor.

Unbalance of coupling

Check coupling whether matching is improper

Non- alignment of shaft center line

Realign the machine unit. Recover the foundation to the correct plane

Resonant vibration of sup-porting structure of the motor

Vibration is serious at the foot of motor. It disappears rapidly together with change of speed or after motor cutting off.

Shaft neck is out of round or bended

Vibration frequency is an integral multiple of rotation frequency. Repair or replace the rotating shaft.

6.5 Low insulation resistanceTrouble of insulation resistance (See Table 11)

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Table 11Trouble Possible causes method of treatment

Low insulation resistance

Moisture dust, conductive particle or other contamination

Clean up the motor and dry it according to the requirements

Mechanical damage Inspect coil support and channel wedge. Inspect whether there are foreign matters or excessive vibration

Coil damage when winding it

Inspect whether it is overloaded, ventilation is restricted, din accumulation is too much, voltage is unbalanced or voltage is unsuitable. Replace the coil.

6.6 Overloading of the motorTrouble or overloading of the motor (See Table 12)

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Table 12Trouble Possible causes Method of treatmentOverheatingof motor inno loadrunning

Mistake in connection of stator winding (such as, method of star connection is misused with method of delta connection)

Check method of connection

Voltage of power supply is too high Check the voltage of main power supply and non-load current

Cooling is ineffective due to blocking of the ventilating passage

Clear off obstacles in the ventilating passage

Wrong rotating direction of fan (single direction rotation for motor is designed)

Check fan and rotating direction of the fan

Overheating of motor when running with load

Overloading of the motor Check the currentVoltage is too high or too low Cheek the voltageThe motor runs in single phase Locate tile broken

location of incoming line

Friction between the stator and rotorWater flow is insufficient or local blocking in water cooler

Inspect the air gap between the stator and rotor. Adjust water pressure, water flow and air discharge

Local over heating of stator

Turn- to- turn short circuit in the stator (over-heating in some coils and buzz noise exists)

Find out the coil which is turn- to-turn short circuited, Replace the coil and repair it

7. Allowable temperature rise of asynchronous motorTemperature limit K of motor (See Table 13)

Table 13

Position of the

motor

A,C. winding of

motor with

power

capacity

greater than

200kW but

A.C.

winding of

motor with

power

capacity of

200 kW

iron

core

Collective

ring

Bearing

Sliding

bearing

Rolli

ng

bear

ing

40

smaller than

5000kW

and below

B

Class

Ther

momet

er

method

---- ---- 80 80

40 55

Resis

tance

method80 80 --- ---

Embed

ded

temper

a ture

decting

method

90 ---- --- ---

F

Class

Ther

momet

er

method

---- ---- 100 90

Resis

tance

method105 105 --- ---

Embed

ded

temper

a ture

decting

method

110 ---- --- ---

Temperature protection : For B Class ,120oC is alarm temperature ,130oC is the cutting temperature . For F Class checking with B Class ,130oC is alarm temperature ,140oC is the cutting temperature .For F Class checking with F Class ,140oC is alarm temperature ,150oC is the cutting temperature .The capacitance over 5000kw ,the temperature protection rise 5oC .

The alarm temperature of sliding bearing is 75oC ,80oC is the cutting temperature ,65oC is the overflow temperature .

The alarm temperature of rolling bearing is 90oC , 95oC is the cutting temperature .

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Instruction of selflubricating end-cap type slide

bearing

While the selflubricating end-cap type slide bearing is used in electric

motor ,the user must refer to the instruction ,inspect and adjust the

bearing .Before operation the following points should be done:

1. Inspeeting the installation of bearing bush ,ensure the position is

right ,especially between connect and operation carry on the last

inspection of steel bush .Ensure the position of bearing bush is no

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change .If there was changed ,install and adjust it again .the following

method is how to make the bearing bush in right position .Put bearing

bush into bearing pedestal and tighten up bearing bush and under bearing

bush .Turning the electric motor while untighten the bearing and bearing

cover and bearing pedestal .

2. Pouring oil and turning the electric motor before start the

motor .the method is : Pouring a little lubricating oil through the view

window of bearing pedestal while somebody turn the shaft .Attention :This

operation must be done before start the motor every time .

3. When let person turn the shaft can’t be carried on .Another method

is point start . Pouring a little lubricating oil through the view window of

bearing pedestal before point start and measuring the temperature of

bearing bush and vibration of bearing .the suitable voltage of point start is

30%-50% of rated voltage .If the voltage can’t be lowed ,we can use full

voltage .

Shenyang Electric Machine Co . ,LTD

Address : tiexi borough weigong street 20#

Postalcode : 110026

Fax :024-25820928

Phone :024-25552213

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