TO-259010499

Manufactured by:Hobart Ground Power

Troy, Ohio 45373, U.S.A

OPERATION

and

INSTRUCTION MANUAL

for

12 PULSE

INPUT FILTERING SYSTEM

SERIES 286409-001

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GENERAL

TO-259 provides details for the 12 Pulse Input Rectification System (12 Pulse) option used on the 60 and90 kVA PoWerMaster® ADV converter, manufactured by Hobart Ground Power Troy, Ohio 45373 U.S.A.This is a factory installed option only, the operation and warranty is fully supported by Hobart GroundPower.

DESCRIPTION

The 12 Pulse Input Rectification System reduces the distortion of the input current drawn by theconverter. This option is useful in applications where the harmonics generated by 6-pulse rectificationmay cause interference with other loads sharing the power distribution bus or additional heating of theprimary power distribution transformer. The input current harmonics are reduced to 12% or less for loadsgreater than 50% of the converter rating.

This is a factory installed option fully contained within the standard package and is fully automatic uponstartup and requires no special attention or regular maintenance. The input will accept any phasesequence of three-phase power, 3 or 4 wire, within the voltage rating specified for the standard converter.

OPERATION

The 12 Pulse Rectification System consists of a thyrister/diode assembly, 6 modules (SCR1 throughSCR6), an input line reactor (L7), a phase shifting input transformer (T3), and two inter-phasetransformers. Figure 1 is a block diagram of the system. The three-phase input voltage is applied to theinput of the phase shifting transformer (T3) through the input line reactor (L7). Two new three-phasevoltages, one shifted +15 degrees and one -15 degrees, relative to the input are generated. Eachthree-phase voltage set is connected to a Full Wave Rectifier bridge consisting of SCR1 through SCR6.The SCR modules are phase controlled only during start-up to limit in-rush current. Each rectifier bridgeproduces a +DC and -DC voltage that are paralleled through two interphase reactors L4 and L5, whosefunction is to force the two bridges to share the load current equally and allow for any differences in DCvoltage produced by each bridge. The output of interphase reactor (L4) is connected to the positive and(L5) to the negative of the DC filter capacitors.

FIGURE 1BLOCK DIAGRAM

Apr. 24/98 Page 1

TO-259 / Operation and Instruction Manual

12 Pulse Input Filtering System - Series 286409

PARTS LIST

NOMENCLATURE UNITS

FIGURE HOBART PER

ITEM NO. PART NO. 1234567 EFF ASSY

- 286409-001 12 PULSE KIT 1

1 286481-001 . 12 PULSE TRANSFORMER (T3) 1

2 286316-001 . MOUNT, UNIVERSAL 4

3 286438 . STUD, TRANSFORMER, ASSY. 4

4 286285-001 . SCR DIODE (SCR4-SCR6) 3

5 283196-003 . THERMAL PAD SCR DIODE 3

6 286395 . SCR BUS BAR 2

7 286488-001 . REACTOR, 3 PHASE INPUT 1

8 286394 . BARRIER, SCR CABLE 1

9 403955-021 . SUPPRESSOR, SEMICONDUCTOR 1

DIAGRAMS

Refer to schematic and connection diagram 286355 included at the end of this manual.

Page 2 Apr. 24/98

TO-259 / Operation and Instruction Manual

12 Pulse Input Filtering System - Series 286409