[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: (ET) motor current





On Wed, 26 Jul 2006, Neil Dennis wrote:

First, if you have an accurate voltmeter / ohmmeter, measure the voltage
drop along the power lead, check the resistance - that should give you a
bllpark reading for the motor current.

D'oh! Good idea, I should have thought of that - essentially use the lead for the motor as a shunt. *smack* (sound of me smacking myself in the forehead)

Do that before you try the 10
amp meter.  I'd guess that the motor draws more than 10 amps but maybe
not.  Wonder, aren't they rated about 1 1/2 hp, that's about 1100 watts
so go from there.

Damn, that's 28 Amps, assuming 39 volts. They presumably don't always pull that much power, only when initialy starting up, and as needed to maintain speed while cutting. Still, that initial startup would likely just blow the ammeter fuse. I'll use the lead as a shunt.

Have you taken the motor apart, maybe the field magnet is cracked, that
could cause the problem.

Nope, haven't taken it apart. I figured I'd first see if I can find some other problem causing it before disassembling the motor. If that is the problem - do the large diameter and small diameter motors use the same field magnets? (I have a spare small motor, but the three I'm using are large ones) If not, perhaps some place has replacement magnets?

Thanks
Mike