Thermal Dynamics Cutmaster 101

[Joker11]

Ok guys, a little unsure about this one even though I am pretty experienced in the electrical arena. Working with 230VAC 60Hz single phase. (15.5kVA)

The Plasma cutter I have pulls 67amps at full output. It is wired with 6/3 SO cable with a Nema 50-P plug.

According to my Ugly's electrical reference the Nema 50-R is a 50amp receptacle.

To add to my confusion, it says to use an 80amp circuit breaker.

I understand derating the 6/3 SO cable due to duty cycle. 100% at 45amps, and 40% at 80amps.

But an 80amp breaker on a 50amp plug? I feel a little uneasy about the 6awg cable too....

Can anyone shed some light on this subject?
:jester:

[Sandy]

Same derating will apply to the whole set-up as long as it's a dedicated circuit for the plazma and/or similar draw welder or less. One reason the call for a 80 amp breaker is likely because they are calling for an 80 amp conventional breaker to counter for the relatively high inrush of current. Is that plaz a high freq start or contact start? An alternative would be a 50 or 60 amp time delay breaker, but those are difficult to get folks to adhere to. So it's simplest to call for an 80. Your good to go.

Unless you are going to set up on 8 foot sheets, one after another for hours on end :), no sweat. As a side note when cutting lighter gage material you can crank the amps down quite a bit. Lets you slow down and concentrate on following a line rather than moving at warp 6 if you are trying freehand.

[Joker11]

Sandy,
No high freq. on this unit, however, no direct contact is required. It has a module they call a "Start Cartridge". I wonder if it is a capacitor of some sort.
You can use a standoff or a direct drag start. It has an auto restart as well for cutting expanded metal.
Also, you are correct that I can turn it down for lighter gauge material. That is why I got this particular model. It will go from 20amps to 80 amps. With a genuine cut on 1inch, a quality cut on 1-1/4 with a severance at 1-1/2inches. Or so the literature claims. I will post in the correct thread once I actually use it. Waiting for my desiccant dryer first. Thanks!

[Sandy]

No high freq. on this unit, however, no direct contact is required. It has a module they call a "Start Cartridge". I wonder if it is a capacitor of some sort.

Yeh when they say "contact start" they actually mean an internal contact which starts the pilot flame. I'm not sure of exactly what all that entails but it's neat for sure. Watch out for that pilot flame. It can be mean. Sounds like a good one. Let us know with a pic or two how it does. :waving: