Motor KBAC wiring problem

Kevin Cross

Kevin Cross

Knifemaker / Craftsman / Service Provider
Joined
Sep 13, 2006
Messages
863
A little help for the electronically challenged please....I recently had the opportunity to pick up a new Leeson 115048 3 HP 1 phase motor cheap. After years of hearing the benefits of variable speed for my grinder I figured now was the time. So I grabbed it. I then got a KBAC 29(1). Wired every thing up according to diagram on the motor and the KBAC manual. Moved jumper for 3 HP. Plugged it in and the indicator lights show that I have power but slow blinking red indicates a short some where.

Any ideas of where to start?

Thanks in advance.
 
Oops, I correct myself, it appears that VFD will run on single phase. I did not know that. I'm not sure what your problem might be.

Well, now as I read more, I think I was right the first time. I believe it has a 3 phase output, so you would need a 3 phase motor.
 
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VFDs require a 3 phase motor. They can take single phase power, but won't work with a single phase motor.
 
A VFD takes in single phase or three phase power and puts out three phase power at a variable frequency. Three phase motors can run at a variety of frequencies. Single phase motors generally run at only 50/60 hertz.
You can't use a VFD on most single phase motors.

Hopefully, you haven't ruined either the VFD or motor, but your post is a good example of why people who are not completely familiar with power and the electronics of VFD's should NOT do any wiring. Many people say they understand most of it, but you can get killed by the part you don't know.
 
Kevin Cross said:
A little help for the electronically challenged please....I recently had the opportunity to pick up a new Leeson 115048 3 HP 1 phase motor cheap. After years of hearing the benefits of variable speed for my grinder I figured now was the time. So I grabbed it. I then got a KBAC 29(1). Wired every thing up according to diagram on the motor and the KBAC manual. Moved jumper for 3 HP. Plugged it in and the indicator lights show that I have power but slow blinking red indicates a short some where.

Any ideas of where to start?

Thanks in advance.
Click to expand...

Read the manual until you understand it.
I say read it once a day for 10 days.


When electrical and motor questions come up, the first thing to do is post good quality brightly lit, large, high quality, photos that you take with a camera not crappy cell phone pics.

Motor name plate
motor wiring

VFD interior and wiring


The wiring to the fuse and power switch that you installed.

I then take the info from those data plates rather than what's written because there's no mistaking that.


Kevin Cross said:
A little help for the electronically challenged please....I recently had the opportunity to pick up a new Leeson 115048 3 HP 1 phase motor cheap. After years of hearing the benefits of variable speed for my grinder I figured now was the time. So I grabbed it. I then got a KBAC 29(1). Wired every thing up according to diagram on the motor and the KBAC manual. Moved jumper for 3 HP. Plugged it in and the indicator lights show that I have power but slow blinking red indicates a short some where.

Any ideas of where to start?

Thanks in advance.
Click to expand...

Whoops

That's it right there

You need a motor that takes 3 phase 220 or 230volts
That's in the manual
 
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Thank you all for the quick replies. My confusion was in thinking the VFD would convert the 1 phase to 3 phase if the motor required it, not that it mandated a 3 phase motor.

Stacy, you are correct. My knowledge is limited but I do realize my limitations. When I wired it "by the book" and immediately got the status light showing a short, I knew it was time to unplug everything and post here. I agree I hope the VFD is not damaged.

Again, thank you all. Time to shop for a new motor!
 
With your indulgence, I will use this situation to emphasize the point I was making about a person only knowing part of what is needed to do this,

"......When I wired it "by the book" and immediately got the status light showing a short...."


You thought you were wiring "by the book", but in fact you were NOT wiring by the book. The "book" clearly showed the three phase output legs L-1, L-2, L-3 and the specs in the "book" as well as on the VFD itself clearly stated that the output is 3Ph. The motor plate stated it was 1Ph and the input was 220VAC with L-1 and L-2 and ground. The symbol that an inexperienced person might not understand was the Φ coming after a 3. Theta means "phase".

To quote Alexander Pope, "A little knowledge is a dangerous thing. (So is a lot.)"
 
if you guys aren't certain of electrical issues don't be afraid to post and ask questions here. I'm sure there is more electrician's
, industrial electricians or automation technologists or experience people willing to help you guys.

Not only do you risk damaging your equipment but causing injury or even worst
To your self. Always be sure to read
The manual.
 
Thanks for emphasizing this again, Stacy. While I am quite knowledgeable in some areas, this is not one of them. I had researched many of the previous threads about this and thought I had a grasp of it. Obviously not.

Now I have learned a bit more and the fact that I did not fry myself, even if I fried the motor and/or the VFD I will chalk up to "educational expense."

I just hope that the next guy reading all the threads will get to mine and not make the same mistake. After all, that's what this forum is all about learning from each other and then passing it on.
 
Kevin Cross said:
Thank you all for the quick replies. My confusion was in thinking the VFD would convert the 1 phase to 3 phase if the motor required it, not that it mandated a 3 phase motor.

Stacy, you are correct. My knowledge is limited but I do realize my limitations. When I wired it "by the book" and immediately got the status light showing a short, I knew it was time to unplug everything and post here. I agree I hope the VFD is not damaged.

Again, thank you all. Time to shop for a new motor!
Click to expand...

The drive should be ok , funny it would indicate short since From line to load your going from 3 phase
To single
Phase. Meaning ... That's right the drive see's a single phase and faults. For example
If you took a 3 phase motor ,
Connected to the drive and disconnected one phase the drive should fault from single phasing. This is a safety interlock to prevent bad things from happening since essentially a 3 phase going to single
Phase is locked rotor. so I doubt you damaged anything unless you actually
Shorted something ... These little drives are fairly sophisticated. They have power transformers and zero sequence transformers to monitor and some can even trend power. The drive was only looking for 3 continuous phases rather then a single phase.

In other words seeing all 3 phases is a permissive to energize. We call these drives smart drives :eagerness::eagerness:
 
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If the VFD has problems when wired to a correct phase (3) motor, send it in to KB Electronics, and they will repair it for much less than the cost of a new one. They're very helpful, and reasonable. You don't even have to explain what you did, they'll simply diagnose and fix the problem, usually without much discourse.


The motor is likely fine.
 
the motor and drive are likely ok. they are fairly sophisticated units Besides if i understand correctly all you did is wire a single phase to a vfd. Unless you shorted something phase to phase or phase to ground... then you have issues ...

I'm not a fan of 1 phase motors or DC motors anyways ... with technology now days 3 phase AC is the cats meow. If only we had 3 phase residential services ...
 
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