VFD Wiring Question

H

huntin'monkey

Joined
Jan 17, 2015
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13
First, thanks to everyone who chimed in on my grinder thread. I pulled the trigger on a 2x72 Alec Steele/84 Engineering grinder. It's set up and ready to go... mostly.


One small problem. I don't have a 220 circuit in my shop and my electicians are booked up until April. The grinder came prewired for 220, but I have an appliance replacement cord kicking around and I could rewire it to regular house power for a month and then wire it back to 220 once I get my circuit installed. The cord I have is 14/3 gauge, and I've been seeing people build theirs with 12/3. Becuase it's going to be on a 115v circuit, will 14 gauge wire be ok?
 
You didn't tell us the HP or amperage of the motor, so we don't know.
With no info, my answer would be to use 12 gauge for 120V on any motor larger than 1HP. 14 gauge would technically be sufficient for 1.5HP, but you could be getting a hot cord after long and hard grinding. At 2HP, 14 gauge would be insufficient.
 
Sorry, I didn't mention the HP or amprage because I'm a dummy when it comes to electronics. The motor is a 2HP unit from US Motors with a listed full load amprage of 6 .0-5 .6/2 .8.

When using 110/115V power, the KBAC 27D (probably should have confirmed that the package includes the 27D) downrates the HP to 1.5, as I'm sure you know, by changing that particular jumper connection. Does that make a difference?

I appreciate what you said about getting a hot cord after a long session at 1.5 HP. Realisticaly, with the projects I've got going right now on the home improvement front, I won't be doing any hardcore grinding for a bit. But I do want to at least be able to get started with this thing and doing some small projects before I get the 220 circuit in, like finishing up some Kiridashis I forged out. I'm like a kid at Christmas who knows what's under the tree and cant' wait to start ripping up wrapping paper.
 
The motor/VFD will pull in the 12-15 amp range (maybe a tad more?) on 115vac at MAX load when you're really hogging With jumper set to 1.5 hp. With lighter grinding the current load could well be in the 5 to 7 amp range since you would only be pulling 1/2 to 1hp range. The amps shown above are for 208-220 vac range with 2.8 amps for 460 vac. For the grinding you'll most likely be doing for the next month or so I'm sure your 14/3 will be just fine.
 
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