VFD Troubleshooting - Undervoltage

Status
Not open for further replies.
Yeah, should be pretty simple to wire a KBAC-48, it'll be 4 wires in, 4 wires out most likely, since it's 3phase 380/460V input, and you'll need to wire the motor according to the high voltage option, assuming it's a 230/460V standard 3 phase AC motor.

At least in this case, assuming you've got the right input and output, it'll be an even number of wires in, and out.

I'm not an electrician, if you're in an industrial setting, utilizing higher voltage 3 phase service, I'd recommend you contact one. This one should be pretty easy for them.
 
Just a quick point that I've not seen mentioned yet - you've checked each leg to neutral and got 110 volts which is good - now check hot to hot (phase A to phase B) to be sure you've got 220 volts. "IF" by chance the recept was wired with both legs (phase) to the same phase you'd have 120 volts to neutral on both legs, but no voltage phase to phase.

You can do this phase to phase voltage check either at recpt or at VFD - I'd check both.
 
"IF" by chance the recept was wired with both legs (phase) to the same phase you'd have 120 volts to neutral on both legs, but no voltage phase to phase.
Click to expand...
This is fairly common mistake with Juniors or Shadetrees.
Mistaking and use Tandem ’breaker rather than a Two Pole ’breaker.
 
Last edited:
A tandem breaker would still deliver both legs just interrupt independently which you don't want. But you're right about shadetrees. My shop being a converted barn, while I was rewiring I found the barn cleaner was running on a tandem breaker with a piece of wire connecting the breaker switches so it would (hopefully) act like a two pole.
 
kuraki said:
A tandem breaker would still deliver both legs just interrupt independently which you don't want.
Click to expand...
A ”Tandem” is two circuitbreakers what obtain supply from a single bussbar. ”Two Pole” is supplied from two bussbars.
But, much like folks referring to split singlephase (correct) as ”two phase”(incorrect) maybe its justified by ones local vernacular and not established convention.
 
This is why I suggested the new poster start a new thread. These last posts are in reference to the old thread from 2017, which I am sure has been long resolved.

I am closing this thread. The new posted should start a new one with his different issue.
 
Status
Not open for further replies.
Back
Top