PM45 voltage way low at cut height

[MountainRef]

My Powermax45 has cut well now for 6 yrs but I (thought) had a problem with my THC going bad and installed new. My arc voltages are about 30% low at cut height. I pulled cover and checked voltage at lead connections on board and they match the THC. I am using raw voltage. Maybe Jim Holt can shine some light on what might be going on. Something I can troubleshoot? Want to be sure before I pay a service center or buy a new machine. Thanks

[weldguy]

I wouldn't worry about it. If your THC is maintaining the correct height and working well just ignore the fact that the reference voltage is a little off. A number of things could cause that and I certainly would not be buying a new machine over it.

[acourtjester]

AS stated above the voltage is just a reference and may be different with different THC packages. Now if this just changed, it does indicate a problem. There are 2 places to look first is the voltage divider board in the Hypertherm, or the THC module it self. Most of the THCs use a 50:1 ratio of the arc voltage, so 100 volt arc will give you a 2 volt out from the hypertherm to the THC which should display 100 on its screen.

[MountainRef]

Using Raw Voltage and THC readout matches actual machine voltage

[jimcolt]

Just a reminder as I have posted this a few hundred times on many forums: The voltage is the feedback for plasma cutting that is used to maintain cut height. Many of these low cost, standalone import height controls have circuitry that seems way out of calibration. So.....I suggest that you do not worry that your voltage readout does not match the Hypertherm cut charts, however be sure that you adjust the voltage so that the height (torch to work distance) does match the suggested cut height in the cut charts. .06" is the most common cut height that provides best cut quality, so if your voltage is at 30 volts and .06" is maintained, then cross out the "book" voltage and write in 30 volts! Height matters, not voltage. Jim Colt