What questions should I ask when ordering a Rheostat from a Manufacturer ?

[adamjohnson]

I am in the process of designing an AC Power supply at my job to test our Surge Protective Devices. Thus far I have ordered a Multi tap Transformer to tap the 7 voltages that we need. We are going to apply 240, 380, 400, 480, 600, 690, and 1,000VAC at 0.5, 2.5, 5.0, and 10 Amps at separate intervals. I ordered an AC resistive load bank but the manufacturer called me back and said that he couldn't do 690 and 1,000VAC. I am now having to design a resistive load on my own. I am speaking to a manufacturer about high powered resistors and was thinking maybe a Rheostat would be better to alternate the resistances to get the selected current level that I need at the selected voltage. The tolerance for the currents at these voltages are +/- 10%. I have found a manufacturer to order Rheostats from. I was wondering what questions should I ask the manufacturer in regards to the rheostat based off of what I am trying to do ? Also what would anyone recommend for the load ? I just figured the high powered relays and high powered resistors would be alot to order and maybe a rheostat would be more simple. Well thanks to anyone who replies.

 

[duke37]

Are you trying to set voltage or current?
For voltage you will need a multitap transformer and a multiway switch. !000V at 10A = 10kW, quite a lump of a transformer.

For current you will need some form of regulator, again 10kW will need a large cabinet with ventilation.

A rheostat will be unreliable unless overspecified.