INSTRUCTIONINSTRUCTIONINSTRUCTIONINSTRUCTIONINSTRUCTIONMANUALMANUALMANUALMANUALMANUAL

DUAL-MODETM

MODEL 114 AMPLIFIERMODEL 114 AMPLIFIERMODEL 114 AMPLIFIERMODEL 114 AMPLIFIERMODEL 114 AMPLIFIER

Systems for Generating Controlled VibrationSystems for Generating Controlled VibrationSystems for Generating Controlled VibrationSystems for Generating Controlled VibrationSystems for Generating Controlled Vibration

5731 Palmer Way, Suite A, Carlsbad, CA 92008 USA (760) 438-4848 FAX (760) 438-8845 apsdynamics@att.net

Serial Number

APS

TTTTTable of Contentsable of Contentsable of Contentsable of Contentsable of Contents

iii

SECTION 1: GENERAL INFORMATIONSCOPE . . . . . . . . . . . . . . . . . . . . . . . . . 1-1DESCRIPTION AND PURPOSE . . . . . . . . . . . . . . 1-1CHARACTERISTICS AND PERFORMANCE

PARAMETERS . . . . . . . . . . . . . . . . . . . . 1-2

SECTION 2: PREPARATION FOR USEUNPACKING AND PACKING . . . . . . . . . . . . . . . 2-1INSTALLATION . . . . . . . . . . . . . . . . . . . . . . 2-1SAFETY INFORMATION . . . . . . . . . . . . . . . . . 2-1

SECTION 3: PRINCIPLES OF OPERATIONCIRCUIT DESCRIPTION . . . . . . . . . . . . . . . . . 3-1OPERATIONAL CONTROLS . . . . . . . . . . . . . . . 3-3

SECTION 4: MAINTENANCEGENERAL . . . . . . . . . . . . . . . . . . . . . . . . 4-1PERFORMANCE CHECKS . . . . . . . . . . . . . . . . 4-1TEST EQUIPMENT REQUIRED . . . . . . . . . . . . . . 4-1TEST PROCEDURE . . . . . . . . . . . . . . . . . . . 4-1ADJUSTMENT PROCEDURES . . . . . . . . . . . . . . 4-2REPAIR/REPLACEMENT ACTION . . . . . . . . . . . . . 4-4

SECTION 5: SUPPORT DOCUMENTATION

Model 114

NOTES

11111General InformationGeneral InformationGeneral InformationGeneral InformationGeneral Information

1-1

SCOPE

This Instruction Manual provides operation and maintenance informationfor the APS Dynamics Model 114 DUAL-MODE Power Amplifier. SerialNumber effectivity of this manual is given on the title page.

DESCRIPTION AND PURPOSE

The Model 114 Power Amplifier is designed to provide drive power forshakers such as the Models 113, 129, 400 and 500. The amplifier hasfeatures which make it particularly useful for studying the dynamiccharacteristics of structures.

The DUAL-MODE feature of the unit allows operation in either a voltageor current amplifier mode, selectable from the front panel. Refer toSection 3 for a full discussion of this feature.

The completely self-contained unit is packaged in a rugged aluminumenclosure suitable for bench or rack mounting. Rack Adapters areincluded for standard 19-in rack mounting. Integral forced air coolinginsures continuous operation with a shaker delivering rated force intoblocked, resistive or reactive loads.

A current monitor signal permits monitoring of the instantaneous outputcurrent amplitude and phase. Protection circuitry will detect an outputshort-to-ground and remove the drive signal.

Model 114

NOTES

Section 1: General Information

1-2

CHARACTERISTICS AND PERFORMANCE PARAMETERS

Output, into shaker reactive load . . . . . . . . . . . 125 V-A rms

Current Output, maximum . . . . . . . . . . . . . . . . 4.0 A rms

Current Peak . . . . . . . . . . . . . . . . . . . . . . 5.6 A peak

Frequency Range . . . . . . . . . . . . . . . . . . . 0-2000 Hz

Maximum Input Signal . . . . . . . . . . . . . . . . . . 2 V peak

Input Impedance . . . . . . . . . . . . . . . . . . . . 100 K ohm

Noise, referred to maximum output . . . . . . . . . . . . . -80 dB

Current Monitor Output . . . . . . . . . . . . . . . . . 250 mV/A

Input Power . . . . . . . . . . . . 120 V (100 V, 230 V Optional)*50/60 Hz, 380 W

Rear Panel ConnectorsPower Output . . . . . . . . . . . . . . . WK3-31S CannonInput and Monitor . . . . . . . . . . . . . . . . . BNC TypeAC Power . . . . . . . . . . . . . . . . . . 3-Pin Receptacle

Weight . . . . . . . . . . . . . . . . . . . . . . . 25 lb, 11.3 kg

Size (H x W x D) (less rack adapters) . . . . 5.22 x 17.0 x 9.25 in.,133 x 432 x 235 mm

EnvironmentalOperating Temperature . . . . . . . . . . . 5 to 50 degrees CStorage Temperature . . . . . . . . . . . -40 to 85 degrees CHumidity . . . . . . . . . . . . . . . . . 90% RH Maximum

* Optional voltages available with original order and are not fieldconvertible.

Model 114

NOTES

22222Preparation for UsePreparation for UsePreparation for UsePreparation for UsePreparation for Use

2-1

UNPACKING AND PACKING

The Model 114 Power Amplifier is packed in a corrugated cardboardbox with foam inserts. The box and inserts should be kept for possiblefuture reshipment of the amplifier. Rack adapters and a power cordare included in this container.

INSTALLATION

The amplifier may be bench mounted or installed in a suitable 19-inrack or cabinet. For rack mounting, use the Rack Mounting Adaptersprovided and the mounting screws in place on the side panels. Thecabinet should provide adequate air flow through screening or louverslocated at the top and bottom of the cabinet. In either case, otherequipment should not be located over or below the amplifier in amanner which blocks the air exhaust. A space of 1-3/4 inch (one rackunit) is recommended.

The Model 114 requires 120 V, 4 A, or optional 100 V, 4 A, 50/60 Hzsingle-phase power. Equipment ordered for 100 V operation is factoryconnected for 100 V.

The input and current monitor output are terminated at rear panel BNCtype connectors. The power output connector is a 3-pin Cannon typeWK3-31S.

The amplifier case is grounded through the power line ground wire.The signal ground is connected to the case at the input connector.

The amplifier output requires an ungrounded load for rated output.Protection circuitry protects the unit against inadvertent groundingof one of the output terminations.

SAFETY INFORMATION

The Model 114 operates from a single-phase power source with oneof the current-carrying conductors at ground potential. Operation frompower sources where both current-carrying conductors are live with

Model 114

NOTES

Section 2: Preparation for Use

2-2

respect to ground is not prohibited, since only the line conductor hasover-current protection within the instrument.

* WARNING *

CONNECT THE SYSTEM INTERCONNECT CABLE TO THEAMPLIFIER OUTPUT AND SHAKER TERMINALS BEFOREAPPLYING POWER TO THE AMPLIFIER.

A 3-wire power cord is provided with a 3-terminal polarized plug forconnection to the power source and safety-ground. The groundterminal of the plug is directly connected to the metal parts of theinstrument. For electric-shock protection, insert this plug in amating outlet with a safety-ground contact.

* WARNING *

DO NOT REMOVE REAR PANEL OR TOP AND BOTTOM COVERSWITH POWER CORD ATTACHED.

Model 114

!

!

NOTES

33333Principles of OperationPrinciples of OperationPrinciples of OperationPrinciples of OperationPrinciples of Operation

3-1

CIRCUIT DESCRIPTION

The Model 114 Power Amplifier consists of two heat sink mountedpower modules, a circuit board containing input amplifiers, a currentmonitor amplifier and an output short-to-ground detector and relay.In addition, a power supply section provides positive and negativevoltage.

The two power modules each contain two self-contained poweroperational amplifiers arranged in a configuration which producesa balanced output of twice the voltage of a single amplifier. Referto the simplified circuit of a power module in Figure 3-1. In the voltageamplifier mode, Amplifier A1 is connected through the control of thefront panel switch as an inverting voltage amplifier with a gain of three.Amplifier A2 is connected as an inverting voltage amplifier having unitygain with input directly from the output of Amplifier A1. Thus the voltageacross the load is twice the voltage output of A1. The output currentsof each power module are summed through equal resistors R. Theseseries resistors reduce the output voltage when the load is resistive.With a reactive load, however, the internal voltage drop is in quadraturewith the load voltage and is less significant. The resistors allow theamplifier to operate over a range of load impedances both resistiveand reactive while minimizing the amplifier dissipation.

In the current amplifier mode, amplifier A1 is connected for currentfeedback. Refer to Figure 3-2. The amplifier output current is sampledin resistor R. Amplifier A2 remains as an inverting voltage amplifierwith unity gain and provides voltage equal to that of A1, as requiredby the current output of A1. Current source A1 in series with voltagesource A2 remains a current source.

Each amplifier is driven by a pre-amplifier with the gain set for five.The pre-amplifier has a set clip level to prevent overdrive.

The current monitor circuit consists of a differential amplifier connectedacross one of the four equal resistors R. The gain of this amplifier isset so that rated output of 4 A rms produces 1 V rms at the CurrentMonitor connector. The Model 114 amplifier is protected against ashort-to-ground at the output. Normally the output is balanced, i.e.,equal and opposite voltage relative to ground. To monitor this condition,the voltages at the output terminals are summed. Normally this sum

Model 114

Section 3: Principles of Operation

3-2Model 114

INPUT

A 2OUTPUTR R

A 1

Figure 3-1 Voltage Amplifier Mode

Figure 3-2 Current Amplifier Mode

RA 1

OUTPUTINPUT

A 2R

NOTES

Section 3: Principles of Operation

3-3

is approximately zero. If an unbalance occurs, such asshort-to-ground, the summed voltage will not be zero. This signalis amplified and when a threshold is exceeded, positive feedbacksaturates and locks-up the sensing amplifier. A fast relay operatesand removes the input signal to the pre-amplifier.

The power supply consists of unregulated, high current positive andnegative 45-V supplies. These provide power directly for the poweroperational amplifiers. The remaining active circuitry is powered fromtwo zener regulated 15-V supplies and two zener regulated 5-Vsupplies located on the input circuit board.

OPERATIONAL CONTROLS

The front panel operational controls are the main POWER switch,the OPERATING MODE selector switch and the AMPLITUDE control.The main POWER switch controls all the power to the unit includingthe cooling fan.

The OPERATING MODE selector switch contains four positions:

1. VOLTAGE

2. VOLTAGE - OFF

3. CURRENT - OFF

4. CURRENT

Operation of this switch under load is permissible. However, changingfrom the Voltage Mode to Current Mode while operating the shakermay cause over displacement of the shaker. The AMPLITUDE controlshould be reduced during this change. Rotating the OPERATINGMODE selector under load, excessive input levels, input transientsas well as a short-to-ground may activate the detector. To reset,rotate the switch to either of the “OFF” positions.

The Voltage Mode is used for general shaker operation. This modeproduces an approximate “constant velocity” response as a functionof frequency in the region of armature suspension resonance. Thismode produces high internal damping in the shaker armature motiondue to the low amplifier source impedance. Voltage Mode operationis retained with the OPERATING MODE switch in the VOLTAGE-OFFposition.

The Current Mode is normally used in modal test excitation orwhenever it is desired that the shaker have minimum effect on thesystem damping. This is particularly important during measurement

Model 114

NOTESof damping by the decay method. For this reason, an OFF position isprovided which retains the current mode operation with the drive signalremoved. Operation of this switch from CURRENT to CURRENT - OFFprovides a convenient means for initiating system response decay.

The response of the shaker driven by the amplifier in the current modeis essentially “constant-force” with varying load conditions and drivefrequency. Note, however, in the vicinity of armature-body suspensionresonance, “constant-force” will produce high relative motion betweenthe body and armature and a sharp increase in force applied to the teststructure.

The AMPLITUDE control allows adjustment of the amplifier outputfrom zero to the maximum rated output. When the control is set fullclockwise, the maximum input signal applied to the amplifier shouldbe adjusted to 2-V peak. A signal above this will be clipped at the2-V peak level.

In the VOLTAGE MODE, the current output depends on the shakerimpedance and the mechanical load impedance. At low frequencies,the shaker may require a small fraction of the voltage required for highfrequencies.

In the CURRENT MODE, the output current is directly related to theinput voltage. A 2-V peak input voltage produces the maximum currentpeak level regardless of shaker impedance on load impedance.

3-4

Section 3: Principles of Operation

Model 114

NOTES

44444MaintenanceMaintenanceMaintenanceMaintenanceMaintenance

4-1

GENERAL

The Model 114 Power Amplifier is designed to be a trouble-free unit,requiring a minimum of checks and adjustments. The amplifier isequipped with two adjustment potentiometers to provide zero dcoffset for the voltage and current modes.

This section contains sub-sections which cover the following:

1. Performance Checks - to verify performance in accordance withCHARACTERISTICS AND PERFORMANCE PARAMETERS.

2. Adjustment Procedures - dc offset adjustments for the voltage andcurrent modes.

PERFORMANCE CHECKS

The following performance checks compare the Model 114 performancewith that given in Section 1.

TEST EQUIPMENT REQUIRED

1. 8-ohm and 4-ohm 150-W resistors or equivalent combination

2. AC voltmeter

3. Oscilloscope

4. Ungrounded (floating common) Multi-meter with 0-50 mV dc rangeor better

5. Sine-wave generator with at least 2-V peak output

TEST PROCEDURE

1. Connect the amplifier to a source of ac power. The line voltageshould be 120 V rms (or optional 100 V rms) for rated output.Equipment ordered for 100 V operation is factory connected for

Model 114

NOTES100 V. Refer to schematic, Main Frame 0352. Leave the powerswitch off until all switch settings and connections to the amplifierand test equipment have been made. Follow this procedure for alltests in Table 4-1.

2. Connect the 8-ohm load resistor between pins 1 and 2 of theoutput connector.

3. Connect the multi-meter across the 8-ohm load (with commonside floating with respect to ground). Set the OPERATING MODEswitch to the VOLTAGE - OFF position.

4. Turn on the amplifier, and measure the dc offset voltage. Ifthe voltage measures over 50 mV dc, refer to ADJUSTMENTPROCEDURES. Repeat this step with the OPERATING MODEswitch set to the CURRENT - OFF position. Remove themulti-meter when this step is complete.

5. Connect the AC voltmeter and oscilloscope inputs between pins1 and 3 (ground) or pins 2 and 3.

6. With the input conditions specified therein, check the Model 114performance as summarized in Table 4-1.

ADJUSTMENT PROCEDURES

1. Remove the top cover from the amplifier by first removing the powercord, then remove four rear panel attachment screws. Displacethe rear panel downward and slide cover backward.

* WARNING *

DO NOT REMOVE REAR PANEL OR TOP AND BOTTOMCOVERS WITH POWER CORD ATTACHED.

2. Re-install the rear panel with the four rear panel attachmentscrews, then install the power cord.

3. With the unit operating, adjust R4 with OPERATING MODEselector in the VOLTAGE - OFF position. Set R4 for an outputvoltage less than 50 mV dc.

4. Repeat with the OPERATING MODE selector in the CURRENT -OFF position. Set R5 for an output voltage less than 50 mV dc.

4-2

Section 4: Maintenance

Model 114

!

NOTES

Section 4: Maintenance

4-3Model 114

5. Replace top cover with power cord removed.

* CAUTION *

WHEN REMOVING THE INTERCONNECT CABLE FROMAMPLIFIER OUTPUT BE SURE TO TURN THE LOCKINGRING CLOCKWISE.

TABLE 4-1

PERFORMANCE RATEDTEST PARAMETER INPUT INPUT PERFORMANCE NO. CHECKED CONDITION SIGNAL LIMIT

1 Voltage output in Oscillator connected 20 Hz, set level for 16 V rms betweenvoltage mode, to input, set OPERATING rated output each output terminationmeasured across MODE switch to and ground, 32 V rms8-ohm load position VOLTAGE total

2 Voltage output as in Same as Test 1 2000 Hz, set level Same as Test 1Test 1 except at for rated outputmaximum frequency

3 Current output in Same as Test 1 except Same as Test 1 8 V rms betweencurrent mode, as OPERATING MODE each output terminationmeasured by voltage switch set to CURRENT and ground, 16 V rmsacross 4-ohm load position total

4 Current output as in Same as Test 3 Same as Test 2 Same as Test 3Test 3 except atmaximum frequency

5 Output noise level in Set OPERATING MODE OPERATING MODE 1.5 mV rms maximumvoltage mode with switch to VOLTAGE - switch to VOLTAGE - between output8-ohm load OFF OFF position termination and ground,

3.0 mV rms total

6 Output noise level in Same as Test 5 except OPERATING MODE Same as Test 5current mode with OPERATING MODE switch in CURRENT -8-ohm load switch set to CURRENT - OFF position

OFF position

7 Current Monitor output Same as Test 1 20 Hz, set level for 1.0 V rms at CURRENTwith 4-ohm load 8 V rms between each MONITOR output

output termination andground

NOTES

4-4

Section 4: Maintenance

Model 114

REPAIR/REPLACEMENT ACTION

If a problem occurs in the operation of the amplifier or partrepair/replacement action becomes necessary, contact:

APS Dynamics, Inc.5731 Palmer Way, Suite ACarlsbad, California 92008

Phone: (760) 438-4848FAX: (760) 438-8845E-mail: apsdynamics@att.net

Please be prepared to give the serial number of the unit, the partnumbers involved, and a complete description of the nature of theproblem.

Refer to SECTION 5, SUPPORT DOCUMENTATION for Parts Lists,Parts Location and Schematics.

NOTES

55555SupporSupporSupporSupporSupport Documentationt Documentationt Documentationt Documentationt Documentation

This section contains the following Support Documentation:

1. Parts List, Model 114, Main Frame

2. Parts List, Circuit Board 8330

3. Parts List, Power Module 8174-2

4. Parts List, Cable Assembly

5. Parts Location, Circuit Board 8330

6. Parts Location, Circuit Board 8341

7. Schematic, Main Frame 0352

8. Schematic, Circuit Board 8330

9. Schematic, Power Module 8341

10. Schematic, Cable Assembly

11. Performance Graphs

12. Applicable Modification/Revision Information

5-1Model 114