Electric Help!

Curtiss Knives

KD Founding Member #1, Knifemaker
Anybody an electrician? I need to take two 1.5hp motors and wire them to 1 on/off switch. The motors are 1.5hp, 1725 rpm, 230/460 3-phase. One will turn clockwise and one counter clockwise, so opposite one another. Do I need a VFD to make this happen. I have single phase 220 power. Helps me please!:beg:
 
David,

I'm not an electrician... but an electrical engineer... so take this with a grain of salt.

I'm going to make a WAG that you are working on some sort of double-grinder??? This is what I'd do. Make sure that both motors are exact same mfg and rating. Get a VFD (one that takes 230V 1-phase in and outputs 230V 3-phase) that'll handle the load of both motors (3hp total) and wire both sets of motor leads to the output from the VFD. By swapping two of the three leads into one of the motors, you should end up with a variable speed set-up with one motor that turns one way and one the other. I imagine a straight phase converter would work if you had no need for variable speed... but I only have experience w/ a VFD setup.

Either way, sounds like you're working on a cool project. :D

Erin

Note: The only VFDs that I have experience with are the NEMA 4X KBAC units from KB Electronics. In their product line, the largest 3-phase motor load that you can feed off a 230V 1-phase input is 2-hp (fed off a 20amp breaker). I'm sure that there are 230V 1-ph units out there made to handle the 3-hp that you are looking for... I believe that Rob sells one with his 3hp VS KMG setup.
 
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Man, you guess good. Guess I'll show some preview pics. Yes it's a double grinder. Still a work in progress. I have made it ready for wheels up to 14" and also a separate fixture for double flat grinding. The pic shown is 8" wheels. The machine will use a 72" belt each side. Thanks for the help.
 

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finally some pictures...that is going to be fun..
 
Ohhhhhh man....
that's a serious looking rig.
I remember the 1st double grinder I saw,in Blade magazine,
by Uncle Al (if I recall right).
Your baby is a monster!
 
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