MAINTENANCE
powermax1250
Service Manual
3-23
4
750 VDC
375 VDC
375 VDC
C94
375 VDC
C98
375 VDC
Bus-bleed and soft-start
resistors for serial numbers
below 1250-008720.
R118 = 3
Ω
R119 = 25k
Ω
R120 = 25k
Ω
80
C100
Test 2 – voltage balance
Test to check the balance of the bus voltage, the power-factor circuit, and the soft-start circuit.
• Verify the system’s serial number. Serial numbers below 1250-008720 have a different power board from
systems with serial numbers above 1250-008720.
• Remove screws from capacitors C94 and C98 before measuring the resistors listed below.
• Check the voltage across the inverter IGBT (Q6).
• Check the voltage across the capacitors (C94, C98) before and during torch operation.
• Voltage across both capacitors should be 375 VDC.
On systems with serial numbers below 1250-008720, if the capacitors are not balanced at 375 VDC, install the
RCD resistor kit (part number 128963). For systems with higher serial numbers, replace the power board.
Note:
All values can be ±15%.
Bus-bleed and soft-start
resistors for serial numbers
above 1250-008720.
R124 = 75k
Ω
R125 = 75k
Ω
R126 = 75k
Ω
R127 = 75k
Ω
Note: Bulk capacitors must be
out of circuit.
R126 = 20.8k
R120 = 21.2k
R125 = 21.0k
R127 = 21.2k
R124 = 24.1k
R119 = 24.1k
Inverter IGBT (Q6)
Summary of Contents for powermax1250
Page 9: ...TABLE OF CONTENTS vi powermax1250 Service Manual ...
Page 47: ...4 MAINTENANCE 3 14 powermax1250 Service Manual Troubleshooting Guide ...
Page 48: ...4 MAINTENANCE powermax1250 Service Manual 3 15 ...
Page 49: ...4 MAINTENANCE 3 16 powermax1250 Service Manual ...
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Page 54: ...MAINTENANCE powermax1250 Service Manual 3 21 4 ...
Page 77: ...MAINTENANCE 3 44 powermax1250 Service Manual ...
Page 85: ...PARTS POWER SUPPLY 4 8 powermax1250 Service Manual ...
Page 97: ...WIRING DIAGRAMS 3 6 4 powermax1250 Service Manual ...