Vfd

[Eagle20]

I have voltage coming into my vfd but nothing coming out and the screen is blank. Is there an internal fuse or is the vfd just bad?

 

[trev150]

Have you signalled a forward or reverse signal?

What about a speed reference?


What model is it?

 

[Eagle20]

It's a power flex. Allen Bradley. When this happens we can't get the display to come back on.

 

[jraef]

If your display is not working, that's usually a sign that the control power supply board in the VFD is dead. That itself is usually a symptom of a larger failure, but you may get lucky and that's all it is. Drive mfrs tend to not use fuses on things like that because it can create risky failure modes.

Don't know enough about the PF drives to know if that's a separate board or a part of a monolithic board now. If it's the latter, it's hopefully still under warranty because the cost to repair will likely approach or exceed the cost to replace.


"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> faq731-376

 

[DickDV]

It makes a huge difference what hp drive we are talking about here. If its 25hp or less and you are sure the keypad itself is not defective, the drive is toast. Throw it away.

Above that hp, you may have some parts of the drive that are serviceable. Larger drives also tend to have internal fuses which often are replaceable.

How about a little more information.

 

[MAGTiger]

Just a thought, as I read your post it occurred to me someone was relaying my problem. Just 4 days ago my drive 25hp ABB stopped and the interface screen was blank. I called tech support and they indicated there was no fuse. So I got to looking around in the panel. Sure enough our electrician put a fuse in the panel ahead of the drive and that was the blown fuse. It didn't occur to me before to check for a fuse since we use a panel breaker to control power the drive. I guess with the SCCR ratings issues in panels these days, more fusing is more common.

Neil

 

[jraef]

But if you have a blown fuse on the input power, the comment "I have voltage coming into my vfd..." would not be true, unless the measurement did not involve L-L testing of all 3 phases...


"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> faq731-376