What would a 75hp 480 vac 3 phase motor draw if it were not connected to anything? Just wired up sitting on a table runnng? Is there a table or a formula anyware all the tables I find are for full load amps.
There are no formulas, too many variables. One rule of thumb I have seen is 75% FLA, but my experience says this is on the high side.
70 to 75% of rated current is about right. The reason - The magnetizing component of the current is the same whether the motor is at full load or no load.
Ed
My experience tells me it's closer to 50% than 75%. 50 may be on the low side though.
FWIW
GJ
[This message has been edited by golf junkie (edited 12-04-2002).]
Just wondering, what's wrong with an amp meter?
Volts,
Baldor lists a 75hp model JPM2551T as FLA @ 208v-176a FLA @ 460v-88a and the no- load current at 30.2a
http://www.baldor.com/products/perf...s&family=Pump%7Cvw%5FACMotors%5FPump [This message has been edited by go-go (edited 12-04-2002).]
Good, informative link, go-go.
FLC/NLC = 87.7/30.2 amperes = 35% [surprisingly low]
Power Factor (25% load) = 53% [rotten!]
PF at zero load is not listed, but likely less than 50%. [Way rotten!]
[This message has been edited by Bjarney (edited 12-04-2002).]
The information was helpful thank you!