Test 7 – torch stuck open (tso), Powermax1250 – Hypertherm Powermax1250 Service Manual User Manual

Page 61

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MAINTENANCE

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powermax1250

Service Manual

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Test 7 – torch stuck open (TSO)

• Check the resistance between the pilot arc IGBT (Q8) and J17. The value should be less than (<) 100

Ω.

• Switch to gas test mode and check the resistance again. The value should be greater than (>) 1k

Ω.

• If the value is less than (<) 100

Ω all the time, check the resistance between the pilot arc IGBT (Q8) and J17

with the torch removed. If the value is less than (<) 100k

Ω, replace the pilot arc IGBT (Q8).

• If the resistance is always greater than (>) 100

Ω, then the electrode/nozzle circuit is open.

– Inspect the wiring to the torch.

– Replace all consumables and verify that the torch will fire.

Note: The retaining cap should be snug, but not over-tightened.

– If the torch plunger does not move freely in the torch head, replace the torch head.

• Verify that the pilot arc IGBT (Q8) is open by placing a jumper wire between J14 and the pilot arc IGBT

(Q8). Then attempt to fire the torch. If the torch fires, replace the pilot arc IGBT (Q8).

Note:

All values are ±25%.

Pilot arc IGBT
Q8

J17

J14

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