Hypertherm HPR800XD Auto Gas Rev.2 - Manual (Page 219)

Maintenance
HPR800XD Auto Gas – 806500 5-5
Sequence of operation
1. Power-up – The system verifies that all of these signals are off at power-up
Coolant flow off
Chopper current off
Transfer off
Phase Loss off
Chopper 1 over-temp off
Magnetics over-temp off
Coolant over-temp off
Plasma start off
2. Purge – Air or N
2
gas flows through torch for 20 seconds
Coolant flow on
Primary contactor closes and the chopper performs a chopper test and a current sensor test
Secondary contactor closes and the system tests the secondary choppers and current sensors
Plasma start off
Both contactors remain closed in the next state
3. Idle
Gas pressure ok
Coolant flow on
Chopper current off
Line voltage ok
4. Preflow – 2 second flow of gas
Primary and secondary contactors are closed
5. Pilot Arc – Current flow between electrode and nozzle
Chopper, main contactor and pilot arc relay are on
High frequency present
Chopper current sensor = pilot arc current
6. Transfer – Pilot arc current sensed on the worklead
7. Ramp-up – Primary chopper current increases to set point and gas changes to cutflow
Coolant flow on
Gas pressure ok
Phase loss on
Line voltage ok
After the primary choppers reach maximum current (400 amps), the secondary choppers increase current
output (if necessary) to a final setpoint
8. Steady State – normal operating parameters
Coolant flow on
Gas pressure ok
Phase loss on
Chopper 1 over-temp off
Magnetics over-temp off
Coolant over-temp off
9. Ramp-down – Current and gas flow decreases after plasma start has been removed
Cutflow gas off
10. Auto Off – 10 second postflow
Main contactors off
Choppers off