Hypertherm HT4001 Plasma Arc Cutting System - Manual (Page 137)

MAINTENANCE
11-96
HT4001
Instruction Manual 6-11
Initial Checks
Before tracking down specific problems, do a visual check and verify proper voltages are present at the power
source, transformer(s) and power distribution board.
1. Disconnect line power by turning main disconnect switch off.
2. Using a Phillips head screwdriver, remove top plate, two side plates, front plate, and rear plate of power unit.
3. Inspect interior of power unit(s) for discoloration on PC boards, or other apparent damage. If a component or
module is obviously defective upon visual inspection, remove and replace it before doing any testing. Refer to
the Parts List section to identify parts and part numbers.
4. If no damage is apparent, plug in the power supply unit(s), and apply power by turning on the main disconnect
switch.
5. Measure the voltage at CON1 between L1, L2 and L3. Refer to Figure 6-1 for detail of CON1. The voltage
between any two of the three points at CON1 should be equal to your supply line voltage. If there is a problem
at this point, disconnect main power and check connections, power cable, and fuses or circuit breaker at main
power disconnect box. Repair and/or replace defective component(s) if necessary.
For the 400 volt CE power supplies, measure the voltage between the U, V and W terminals of TB5 in the EMI
filter located on the top of the HT4001 power supply. Refer to Appendix C. Also refer to the wiring diagram in
Section 8, if required. The voltage between any two of the three terminals should be equal to the supply
voltage. If there is a problem at this point, disconnect main power and check connections, power cable, and
fuses at line disconnect switch. Repair and/or replace defective component(s) if necessary.
For the 200/220 – volt power supplies, measure the voltage between the L1, L2 and L3 terminals of TB5 located
on the top of the HT4001 power supply. Refer to Appendix D. Also refer to the wiring diagram in Section 8, if
required. The voltage between any two of the three terminals should be equal to the supply voltage (200 or
220 VAC). If there is a problem at this point, disconnect main power and check connections, power cable, and
fuses at line disconnect switch. Repair and/or replace defective component(s) if necessary.
WARNING
SHOCK HAZARD: Always use caution when servicing a power supply when plugged in and the covers
are removed. Dangerous voltages exist within the power supply which could cause injury or death.
(Continued on page 6-13)