Rotary Phase Converter & Flicker

[bwen08]

I can't seem to find the magic site, paper or person to provide the info on rotary phase converters I'm after, and I bet someone here knows...

For generalization, assume someone purchases a 30HP RPC to provide 3 phase power to a 15HP motor. What is the general inrush/flicker characteristics of the 30HP phase converter? Also if the 15HP motor starts locked rotor, how does this translate through the RPC?

It's always been easier to just come up with the flicker of a locked-rotor of specific HP for approval for connection (never know what people do after the fact down the road without re-approval) but I'd like to actually know the starting characteristics of a RPC setup.

Thanks.

 

[itsmoked]

The starting characteristic is the same as an unloaded 30hp single phase motor. Nasty! Take the nameplate FLA current and multiply it by 7 for the worst case. This usually results in a situation where the single phase network can't even supply the demanded starting load thru its impedance. This results in something less than 7X like maybe 5X and an extended starting time out to about 2X the usual time.

With smaller RPCs this isn't as much of a demand on the network and they get their higher demand with a snappier startup time, more inline with a normal unloaded start.

Keith Cress
kcress -

http://www.flaminsystems.com