I've got three 480 volt plasma cutters my son is going to test at work. He asked me to get them all strapped to a pallet and the plugs installed so he can quickly just plug in and see if the machine works.
OK, I found three 480 plugs. They have X Y Z and G connections. I'll put the green ground wire on the G. Is there a convention for the three hot wires? Red, black and white. Does it matter?
I'm in luck, the group's greatest EE has offered to help re wire to
Karl
It's unlikely that a plasma cutter will be concerned with phase rotation. Possibly a cooling fan could run backwards in the very unlikely event they used a 3ph motor, but it would still be moving air.
If I were designing something like a plasma cutter I'd try very hard to either make it phase agnostic, or have some interlock that made it refuse to go in the event the phase was backwards.
Sensible would be to use a single-phase motor running off of one leg. But I don't design those things, so what do I know?
I would expect most plasma cutters, except perhaps the very oldest, to be using commodity muffin fans which are all single phase AC or are DC. It is very rare to find small fractional HP 3ph motors, but I have seen at least one, so they do exist.
White is the color code for neutral, if using it as a phase conductor it must be marked a different color, in this case blue would be the appropriate color for the third phase conductor. Typical order would be black, red, blue.
It may be a good idea to do so, but it's not required in a flexible cord.
In the US, the color convention for 277 / 480/3 is normally as follows:
A phase - brown
B phase - orange
C phase - yellow
neutral - gray
Well I got three more - thermodynamics PAK5XT.
The manual shows a jumper board. But its not in the machine. Still, I'm almost sure it can be rewired. After all a plasma cutter is mostly just a DC power supply. The start circuits just use 110 and 24 volt.
Karl
Still a bad idea. I have been involved in investigating one accident involving just this same white misusage in the electrical utility field. The "white" phase (should be marked yellow or black) and neutral connection became mixed up on a rather large capacity system.
---------
----------- On Thu, 30 Jun 2011 13:34:16 -0500, "Pete C." wrote: White is the color code for neutral, if using it as a phase conductor it must be marked a different color, in this case blue would be the appropriate color for the third phase conductor. Typical order would be black, red, blue.
Yea, but when was the last time you saw x-4 SO cable with any color choices other than black, red, white and green in the US?
whoops.
what happened in the accident?
Nobody was hurt, only the system, slightly and a few thousand customers suffered outages for an hour, but a few Linemen where scared out of their lives when the underground vault went pop with in a few blocks each direction from the cable.
White phase is the name of the centre phase but **NEVER** marked white in colour. That is reserved for load carrying conductors at close to ground potential only.
---------------
what happened in the accident?
--------- Josepi wrote: Still a bad idea. I have been involved in investigating one accident involving just this same white misusage in the electrical utility field. The "white" phase (should be marked yellow or black) and neutral connection became mixed up on a rather large capacity system.
How do they label/identify those underground cables? Physically, they all look the same.
They do have label slide in holders for some of the cables in vaults. Other than that they are all UV resistant black. Good maps and documentation is an absolute must and the law.
---------------
----------
Josepi wrote:
Have something to add? Share your thoughts — no account required.
Ask the community — no account required