Phase converter

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Hi,       I have a 3hp rotary phase converter that I use for running a sheet metal shear. Can I run a 3 phase plasma cutter on that phase converter?
Reply:Hmmm,,, I an exactly sure, I think it may depend on the type. A lot of electronics do not like the power from them. Is this a cutter you are buying or have?? Elaborate a bit. Many of the new ones run on all kinds of power and if I was buying I would get one with this in mind. No point in converting power unless you have to.www.urkafarms.com
Reply:It depends. I'd contact the plasma manufacturer's technical people, preferably with as much detail about the rotary converter as you can supply.Possible issues: many rotaries rely on the driven load to provide stability-the driven motor is acting like a rotary transformer similarly to the converter. The converter provides enough on the third leg to get the motor to start, then they work together to produce a stable third phase. What this means is that, under load, the generated leg is not very votage stable. For a three phase non-motorized machine, this can be an issue. Less so if the input is a three phase transformer than if it is a rectify-on-input design, but either way, the less stable generated phase will provide much less than it's share of the power (the nature of most of these loads is that they draw at the voltage peak only) and the rectifiers for the line-connected phase will be (potentially) overloaded, as they carry much more than their rated ahare of the load. The output of hte rectifier stage may also be poorly rgulated, leading to poor operation. Another problem is that the current load of the rectifiers can drive the rotary unit ouf of stable rotation, and/or overload it very heavily (the current draw waveform is centered at the voltage peaks, which, to keep it simple, transformers don't like. power supply transformers for many digital applications are much larger than the resistive load equivelants for vacuum tubes rated the same power)Last edited by enlpck; 09-13-2004 at 08:21 PM.
Reply:Thanks enlpck,, I forget all that stuff, the details. Also if i read that correct he said 3 hp, that isnt much power. It isnt going to run much of a cutter, I doubt if they make 3 ph cutters that small.www.urkafarms.com