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andy_b
08-10-2005, 07:48 AM
i was playing around with on old 5hp motor i have. on the tag it is stamped 220V 3ph, 1155 RPM, 5hp, 14.4 Amps full load. this bad boy weighs about 250 pounds (maybe more). i think i posted about it when i first hauled it home (it is the one with 1" endplay and no thrust bearings, the rotor is centered by the magnetic field).

so i hooked it up to my 5hp RPC and it spun up to speed in a second or so. i clamped the current probe on it and the readings were 16.9A, 17.4A and 5.5A. without any of you actually seeing the motor, does it sound like a phase balance issue, or a problem with the motor windings? i didn't grab the voltages per leg, so i'll try to get that info in the next day or so. i also didn't think to check the winding resistances, so i'll have to check them as well.

i'm hoping it is a phase balance issue that i can correct as i wanted to use the motor on a big old bandsaw i dragged home. then again, how much of a concern do you think the current imbalance is if everything stays cool and runs smoothly?

andy b.

Joel
08-10-2005, 04:11 PM
You might want to post this question on the PM phase converter forum:

http://www.practicalmachinist.com/ubb/ultimatebb.php?ubb=forum;f=3