Maintenance
HPR800XD Auto Gas  –  806500  5-41
Start circuit functional schematic
Start circuit troubleshooting
Start-circuit PCB1
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 impedance to the pilot arc lead to aid in 
transferring the arc to the workpiece. See schematic below.
Plasma power supply
Choke
Diode
Start circuit
Cutting 
arc
Pilot 
arc
Power 
resistor
Control 
logic
 ALEL Caps
Chopper
 IGBT
DANGER
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.