Hypertherm HD4070 Rev.8 - Manual (Page 159)

MAINTENANCE
5-12 HD4070 Instruction Manual
1
U
V
W
PE
Power Measurement
Note: Check lines in the following order:
U to V
U to W
V to W
Check each line to ground. If one
line is 10% or higher than the other two,
put that leg on U.
5. Measure the voltage between the W, V and U terminals of TB1 located on the right side of the power supply.
See figure above. Also refer to the wiring diagram in Section 7, if required. The voltage between any 2 of the 3
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 or replace any defective
component.
WARNING
There is line voltage at the contactor after the line disconnect switch is ON, even if the the circuit breaker
on the power supply is OFF. Use extreme care when measuring primary power in these areas. Voltages
present at the terminal block and contactors can cause injury or death.