Hypertherm HSD130 HySpeed Plasma - Manual (Page 175)

MAINTENANCE
HySpeed HSD130 RHF Instruction Manual 5-29
Start circuit functional schematic
Start-circuit troubleshooting
Power supply
control board
PCB2: Start-circuit
Operation
The start circuit is a high-speed switch that quickly transfers the pilot arc current from the pilot arc lead to the work lead.
The start circuit performs 2 functions:
1. It allows the initial pilot arc current to flow through the pilot arc lead quickly, with little impedance.
2. After initial pilot arc current is established, the start circuit introduces resistance to the pilot arc lead to aid in
transferring the arc to the workpiece. See schematic below.
DANGER
SHOCK HAZARD: Always use extreme caution when servicing a power supply when it is plugged in and
the covers are removed. Dangerous voltages exist within the power supply which could cause injury or
death.