COMPONENT CODE 09

PARTS & SERVICE (C)

REF NO. AA10122G
DATE February 28, 2017
NEWS Page 1 of 17
This Parts & Service News Bulletin supersedes the previous issuance AA10122F, dated July 26, 2012. Discard AA10122F.
SUBJECT: AC DRIVE SYSTEM CONTROL GROUP LINK VOLTAGE POTENTIAL /
REPAIR & MAINTENANCE PROCEDURE
PURPOSE: To notify the field of recommended instructions to properly measure the AC sys-
tem DC link voltage before performing any work on any high voltage compo-
nents, and to provide a discharge procedure for the AC system DC link
capacitors in the case of failure of the built-in discharge circuits in the GE IGBT
control groups.
APPLICATION: Komatsu Electric Drive Dump Trucks:
830E-AC: A30001-A30071, A30079-A30108;
830E-1AC: A30072-A30078, A30109 & Up;
930E: 32604-32816, A30019, A30026-A30120;
930E-2: A30012, A30098, A30100, A30121-A30293, A30295-A30303;
930E-2SE: A30183;
930E-3: A30294, A30304-A30461;
930E-3SE: A30171-A30389;
930E-4: A30462 & Up;
930E-4SE: A30587 & Up;
930E-4AT: A30504 & Up;
960E-1: A30001, A30003 - A30026;
960E-2: A30027 & Up;
980E-4: A40003 & Up
FAILURE CODE: 091CZ9
DESCRIPTION:

The control cabinets on the specified trucks are each equipped with two capacitor charge lights, one on
the exterior of the cabinet and one in the interior. The capacitor charge lights, when off, indicate to ser-
vice personnel that the drive system is safe to work on. Certain drive system failures, however, can result
in a condition where one or more capacitors can remain in a charged state even though the capacitor
charge lights are off.
Because a danger can still exist with the capacitor charge lights off, it is necessary to adhere to the follow-
ing instructions before touching or servicing drive system components. Only authorized service person-
nel are allowed to service the drive system.
Refer to the service manual for rules when servicing the drive system on the specified trucks. Adhere to
the proper procedures for disabling the drive system.

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NECESSARY TOOLS

• 2000 VDC meter (Komatsu p/n

PC3186) (Bierer RCDC 1000 or
equivalent)

FIGURE 1. VOLT METER (PC3186)

• Personal Protective Equipment (PPE) such as insulating gloves (58B-06-00790) for working with the
2000 VDC meter

• Grounding stick pair (Komatsu p/n PC3299) (HVR Advanced

Power Components MAS-000039 Ground Stick Pair or
equivalent)

• Multimeter for ground resistance measurement

FIGURE 2. GROUNDING

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Custom Meter Kit (58B-06-00800) is also available. This meter kit includes a carry case along with insu-
lated gloves and extra probe tips. One set of handle extensions (2) and handles (4) can be switched
between the volt meter probes and the capacitor discharge probes.

TABLE 1: CUSTOM METER KIT (58B-06-00800)

Item Part Number Description Quantity
1. 58B-06-00700 Volt Meter Probes 1
2. 58B-06-00730 Handle Extension 2
3. 58B-06-00740 Hand Guard 2
4. 58B-06-00720 Handle 2
5. 58B-06-00710 RCDC Lead 1
6. 58B-06-00750 Probe Tip (cupped) 2
7. 58B-06-00770 Power Supply / Tester (100V) 1
8. 58B-06-00780 Capacitor Discharge Probes 1
9. 58B-06-00790 Insulated Gloves 1
10. 58B-06-00760 Carry Case 1

FIGURE 3. CUSTOM METER KIT

1. Volt Meter Probes 5. RCDC Lead 9. Insulated Gloves
2. Handle Extension 6. Probe Tip 10.Carry Case
3. Hand Guard 7. Power Supply / Tester (100V)
4. Handle 8. Capacitor Discharge Probes

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WARNINGS AND CAUTIONS
All applicable local mine, government, and industry rules for working with high voltage must be
followed. Required personal protective equipment, including but not limited to safety shoes, high voltage
gloves, and safety glasses must be worn.
Safety cautions and warnings appear throughout the instructions. WARNING indicates the potential for
personal injury and CAUTION indicates the potential for equipment damage. Read the following
warnings prior to working on this drive system.

Hazardous voltages are present in this equipment. Ensure that the Control Power Switch (CPS) is in
the OFF position and that the Generator Field Contactor (GFCO) switch is in the CUTOUT position
before attempting any work on the drive system components. Check that Capacitor Charge Lights
(CCL’s) are not illuminated.

Use measurement and protective equipment rated for 2000 VDC minimum to verify that no voltage is
present before touching any electrical terminal.

Verify functionality of the measurement equipment using site-approved procedures both before and
after performing control group measurements.
Failure to observe these precautions may result in death or serious personal injury.

Verify that the Capacitor Charge Light (CCL) above the high voltage contactor area is not illuminated
before opening the doors to the high voltage area or the high voltage contactor area.

Use measurement and protective equipment rated for 2000 VDC minimum to verify that no voltage is
present before touching any terminal.

Verify functionality of the measurement equipment using site-approved procedures both before and
after performing control group measurements.

Failure to observe these precautions may result in death or serious personal injury.

Hazardous voltages are present in this equipment. Avoid touching any energized equipment when the
door to the low voltage area is open.

Failure to do so may result in personal injury and equipment damage.

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Hazardous voltages may be present in this equipment even if the engine and capacitor charge lights
are off.

Use measurement and protective equipment rated for 2000 VDC minimum to verify that no voltage is
present before touching any terminal.

Verify functionality of the measurement equipment using site-approved procedures both before and
after performing control group measurements.

Failure to observe these precautions may result in death or serious personal injury.

Voltages in excess of 1500 VDC may be present. Any measurement and/or protective equipment used
must be rated at 2000 VDC minimum.

Verify functionality of the measurement equipment using site-approved procedures both before and
after performing control group measurements.

Failure to observe these precautions may result in death or serious personal injury.

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MANUAL DC LINK CAPACITOR DISCHARGE PROCEDURE
PREPARATION
Follow any and all local and site specific procedures and requirements for working on off-highway
mining equipment.

1. Verify that the engine is off and the parking brake is on.
2. Verify that the generator field contactor (GF) switch (2, Figure 4) in the low voltage area of the con-
trol cabinet is in the CUTOUT position.
3. Move the Control Power Switch (1) to the ON position for a minimum of 30 seconds. Then, turn the
control power switch to the OFF position.
(With control power on, an RP contactor closes and discharges the DC link through the retarding
grids in less than 10 seconds.)

FIGURE 4. INFORMATION DISPLAY PANEL

1. Control Power Switch 3. Capacitor Charge
2. GF Cutout Switch Light

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NOTE: In KG527 control groups, RP1 is the normal discharge path. Refer to Figure 5.

FIGURE 5. KG527 DISCHARGE PATH

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NOTE: In KG537 and most KG535 groups, RP2 is the normal discharge path. In KG535 groups
containing an RP3 contactor, RP2 and RP3 are alternated as the normal discharge path. Refer to
Figure 6.

FIGURE 6. KG535 AND K537 DISCHARGE PATH

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CAPACITOR CHARGE LIGHTS
4. Observe both capacitor charge lights (CCL1, CCL2). CCL1 is on the outside of the contactor box.
CCL2 is on the switch panel inside the low voltage area. The lights will stay illuminated as long as
the voltage on the DC link is greater than 50 VDC. Refer to Figure 7. (17KG535 is shown; other
groups are similar.)

FIGURE 7. CAPACITOR CHARGE LIGHTS

1. Exterior Capacitor Charge Light (CCL2) 3. Information Display Panel
2. Interior Capacitor Charge Light (CCL1) 4. DC Link Capacitors

Hazardous voltages may be present in this equipment even if the engine and capacitor charge lights
are off.

Use measurement and protective equipment rated for 2000 VDC minimum to verify that no voltage is
present before touching any terminal.

Verify functionality of the measurement equipment using site-approved procedures both before and
after performing control group measurements.

Failure to observe these precautions may result in death or serious personal injury.

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FAILURE OF DISCHARGE SYSTEM
5. If the capacitor charge lights remain illuminated, a failure of the normal (fast) capacitor discharge
system (RP discharge path) has likely occurred. The slow discharge resistors that are hard wired
across the DC link should then discharge the capacitors. The slow discharge resistors will discharge
the DC link to less than 1 VDC in under 7.5 minutes. If after 7.5 minutes, the capacitor charge lights
are still illuminated, it must be assumed that the automatic discharge system is not working and that
high voltage is present in the high voltage area.

MEASURING DC VOLTAGE ON CAPACITORS

6. Use volt meter tester (58B-06-00770), test the volt meter for proper operation. Voltage should read
100 VDC. If the voltmeter fails the test, repair or replace the volt meter. Do not proceed to Step 8
unless the volt meter is functioning properly.
7. Open the high voltage area doors.
8. With a suitable high voltage meter rated for at least 2000 VDC, such as (PC3186) or (58B-06-
00800) or equivalent, plus suitable protective equipment, measure the voltage across each of the DC
link capacitors. Place one meter lead on the positive (+) capacitor terminal, and the other meter lead
on the negative (-) capacitor terminal, and observe the voltage. See Figure 8 and Figure 9. If the volt-
age is less than 1.0 V the capacitor is sufficiently discharged. Repeat on all DC Link capacitors. If
the voltage of any capacitor is above 1.0 V, manually discharge the capacitor as described in “MAN-
UAL DISCHARGE OF CAPACITORS” on page 11.
9. After checking all DC link capacitors, test the volt meter again using the volt meter tester (58B-06-
00770). Voltage should read 100 VDC. If the voltmeter does not indicate 100 VDC, repair or replace
the volt meter. Do not proceed beyond this step unless the volt meter is functioning properly.
10. If all DC link capacitors indicated 0 VDC, proceed to “SHORT ISOLATED CAPACITOR TERMI-
NALS” on page 14. If any DC link capacitors indicated more than 1 VDC, the capacitors must be
manually discharged before performing any maintenance. Refer to “MANUAL DISCHARGE OF
CAPACITORS” on page 11 for instructions.

FIGURE 8. DC METER ON CAPACITOR

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FIGURE 9. CAPACITOR TERMINAL POLARITY

MANUAL DISCHARGE OF CAPACITORS

If the voltage is greater than 1V on any of the capacitors, the capacitor must be manually discharged.
With a suitable capacitor discharge device, such as ground stick pair (PC3299) or the grounding sticks
from Custom Meter Kit (58B-06-00800), discharge the capacitors where needed per the following
instructions:
1. Determine which capacitors must be discharged by check for voltage starting at “MANUAL DC
LINK CAPACITOR DISCHARGE PROCEDURE” on page 6.
2. With the control cabinet high voltage compartment doors closed, connect the ground stick pair
ground lead to ground. The most convenient location is the middle top bolt that attaches the door
center post to the control cabinet frame.
3. Verify the ground connection and ground stick resistance levels. Measure the resistance between
each individual ground stick tip to either the GND1 or GND2 ground block in the low voltage com-
partment of the control cabinet using a multimeter (Figure 10). Ensure that the resistance is within
the manufacturer’s specifications for the ground sticks. If the readings are not within specifications,
repair or replace the grounding sticks. Do not proceed any further until the grounding sticks are
within specifications.
For grounding sticks (PC3299) or (58B-06-00800), the valid range is 80 to 125 ohms per stick.

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FIGURE 10. GROUNDING STICK LEAD CONNECTION AND CHECK

Hazardous voltages are present in this equipment. Avoid touching any energized equipment when the
door to the low voltage area is open. Failure to do so may result in personal injury and equipment
damage.

Voltages in excess of 1500 VDC may be present. Any measurement and/or protective equipment used
must be rated at 2000 VDC minimum.

Verify functionality of the measurement equipment using site-approved procedures both before and
after performing control group measurements.

Failure to observe these precautions may result in death or serious personal injury.

4. Discharge the relevant capacitors. Open the door(s) and place one grounding stick on one of the pos-
itive (+) capacitor terminals and the other on the diagonally located negative (-) terminal. Refer to
Figure 9 and Figure 11. Attempt to minimize the time between application of the positive stick and
the negative stick so that the current flow will be positive to negative rather than either to ground.
Leave sticks in place until the capacitors are discharged. Refer to Figure 11.
NOTE: On the capacitors located behind the door post, it is difficult to access diagonal terminals on the
same capacitor. If using adjacent terminals, use care to keep the tips separated while discharging or else
use a positive terminal on one capacitor and negative terminal of the adjacent capacitor on the same bus
bar.

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For grounding sticks (PC3299) or (58B-06-00800), the discharge times from 2,000 volts are:
• 15 seconds (maximum) for 2 capacitors
• 75 seconds (maximum) for 10 capacitors
5. To ensure the discharge tool is working properly, verify the ground connection and ground stick
resistance levels. Measure the resistance between each individual ground stick tip to either the
GND1 or GND2 ground block in the low voltage compartment of the control cabinet using a multi-
meter (Figure 10). Ensure that the resistance is within the manufacturer’s specifications for the
ground sticks.

For grounding sticks (PC3299) or (58B-06-00800), the valid range is 80 to 125 ohms per stick.

6. Re-test for voltage on all capacitors as described in “MANUAL DC LINK CAPACITOR DIS-
CHARGE PROCEDURE” on page 6. The discharge procedure must be repeated on all capacitors
that indicated 1 VDC or higher.
7. After it is confirmed that all capacitors are fully discharged, proceed to “SHORT ISOLATED
CAPACITOR TERMINALS” on page 14.

FIGURE 11. APPLICATION OF GROUNDING STICKS TO

CAPACITOR TERMINALS

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SHORT ISOLATED CAPACITOR TERMINALS

Hazardous voltages may be present in this equipment even if the engine and Capacitor Charge lights
are off.

Use measurement and protective equipment rated for 2000 VDC minimum to verify that no voltage is
present before touching any terminal.

Verify functionality of the measurement equipment using site-approved procedures both before and
after performing control group measurements.

Failure to observe these precautions may result in death or serious personal injury.

1. Before performing and service work, any capacitor that is isolated from the DC link and confirmed
discharged must have its terminals electrically shorted together to prevent static charge build up. Use
bare wire to jumper all four terminals on the capacitor. See Figure 12.
2. Proceed to troubleshoot and repair the control group to restore it to original functionality.
3. After repairs are completed, remove the bare wires before starting the engine.

FIGURE 12. JUMPER ALL TERMINALS ON ISOLATED CAPACITOR

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WARNING DECALS
A new decal (Figure 13) has been created to replace the current decal on the control cabinet for all AC
drive trucks with GE IGBT drive systems. A separate decal (Figure 14) has been created to replace the
current decal on all trucks with GTO drive systems. The new decals provide added instructions for check-
ing the state of charge for the drive system capacitors.

FIGURE 13. WB3777 DECAL FIGURE 14. 58F-93-00000 DECAL

TABLE 1. HIGH VOLTAGE WARNING DECALS

New Control Cabinet New Control Cabinet

Previous Decal Language
Decal (IGBT) Decal (GTO)

WB2477 WB3777 58F-93-00000 English

WB2530 WB3864 58F-93-00010 Spanish

WB3280 WB3862 58F-93-00040 Portuguese

WB3333 WB3865 58F-93-00020 Chinese

WB2636 WB3863 -- Bahashi

-- 58F-93-40080 59F-93-00030 Russian

-- 58E-93-00390 59F-93-00050 French

-- WB3978 -- Mongolian

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Decal (Figure 15) will be added to information dis-

play panel (3, Figure 7) inside of the control cabinet.
Refer to Table 2.

FIGURE 15. WB3876 DECAL

TABLE 2. INTERIOR HIGH VOLTAGE WARNING DECALS

New Decal Language

WB3876 English

WB3897 Spanish

WB3895 Portuguese

WB3896 Chinese

WB3894 Bahashi

Only on trucks with the IGBT drive systems, decal

(Figure 16) will replace the four decals currently on
the retarding grid and the two decals on the contactor
box. Refer to Table 3 for part number replacement
information.

FIGURE 16. 58B-93-00410 DECAL

TABLE 3. GRID/CONTACTOR BOX HIGH VOLTAGE WARNING DECALS

Previous Decal New Decal Language

WB2477 58B-93-00410 English

WB2530 58B-93-00470 Spanish

WB3280 58E-93-10030 Portuguese

WB3333 58B-93-00480 Chinese

WB2636 58E-93-10160 Bahashi

-- 58E-93-00500 French

-- 58F-93-40100 Russian

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Note the location of the new decals as shown in Figure 17.

1 1

1 2

72466

FIGURE 17. DECAL LOCATIONS (IGBT CONTROL CABINETS)

1. Decal (58B-93-00410) 3. Decal (WB3876) (Inside of the
2. Decal (WB3777) control cabinet)

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