Inrush Testing Power Supply

[BrentW]

I need to do some inrush testing for a PMDC motor. The voltage is 280VDC and I expect the inrush to be between 47 and 55 amps. I need to supply the current for less than 10 seconds. I could get a large DC power supply but the cost of that and the associated wiring is quite expensive especially because of the short run time. I was wondering about using a capacitor bank that would charge slowly from a single or 3 phase power source and hold a fixed DC output voltage. I looked for something commercially available but I am not sure what I am looking for. If anyone has some ideas I would appreciate it.

 

[Skogsgurra]

I would go to a garage or a battery seller and rent enough 12 V lead batteries. Or, better bring the motor to them and do the testing. Lead batteries have a very low internal resistance and can easily deliver a constant voltage over ten seconds.

Using a capacitor bank is not a good alternative. If you want the voltage to stay reasonable constant for ten seconds at 50 A, you need to supply 500 As. To keep voltage within 10 V, you then need 50 F. Fifty farads at, say, 300 V is a lot of capacitors. Even if you use supercapacitors with their relatively high internal resistance.

Gunnar Englund

http://www.gke.org

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Half full - Half empty? I don't mind. It's what in it that counts.

 

[bobmcbride]

Even the labs that can certify/test motors use a "wall of lead acid batteries" to test DC motors.

 

[dpmac]

When switchgear batteries are replaced or taken out of the circuit for service some companies simply roll in a temporary "cart" or "carts" with batteries configured for the proper voltage. You should be able to rent those "carts" from a larger battery supply company. A few phone calls should get you pointed in the right direction locally.