Hypertherm H401 Power Supplies - Manual (Page 40)

MAINTENANCE AND TROUBLESHOOTING
5-2 H401 & H601 Instruction Manual
4
Routine Maintenance
Clean, service and inspect the H401 and H601 power supplies at 6-month intervals.
Power Supply Circuit Description
The H401 and H601 power supplies are 3-phase transformer-rectifier type, D.C. power sources using SCRs in a
full-wave bridge rectifier circuit. Low rms ripple current is achieved through use of 6 SCRs into an inductor. Filters
are provided to protect the SCRs from high-voltage transients and high-frequency currents from the plasma arc
ignition circuit. A thermostat protects transformer windings from overload and overheated conditions. The
thermostat resets automatically when the transformers return to safe operating temperatures. Circuit boards control
the SCRs. The current can be adjusted from the front panel mounted potentiometer or by a remote potentiometer.
• Remove side panels and blow out any dust with a low pressure dry air line.
• Clean air passages and cooling fans.
• Check for loose wiring and components. Make repairs as necessary.
• Lubricate the fan motor(s) every 2 years with SAE 20 weight motor oil.
WARNING
E LECTRICAL SHOCK CAN KILL
Shut off all power supplies at their primary disconnect switches. In the U.S., use a “lock-out/tag-out”
procedure. In other countries, follow appropriate local or national safety procedures. Shut off all
plasma control circuits to prevent control power from entering the power supply. Verify with a
voltmeter that no power is present on the power supply primary and control circuit terminals
(L1, L2, L3, 1T-1 and 1T-2).
WARNING
Parallel Systems
ELECTRICAL SHOCK CAN KILL
If the power supply is used in parallel with another power supply, or used as a slave unit with
another power supply, both line disconnect switches must be in the OFF position and remain in the
OFF position during installation and maintenance work.