VFD went pop

insanity

insanity

Joined
Feb 28, 2002
Messages
392
So my toshiba vfd made a nice loud poping noise. It no longer works. Are these things worth fixing? Any suggestions?

Wayne S
 
Hello Wayne

What is the part number for your VFD? What were the operating conditions when the VFD popped? Do you have any pictures of the insides? They sometimes are able to repair the VFD's, if not damaged too badly.

Phil
 
As many users have learned,VFD's and grinding dust won't mix.Pop goes the weasel.It takes a special enclosure (NEMA 4 ) to keep the dust out.
 
It is/was a VF-S7 series 1Ph 200v-1.5kW. The insides look fine, there wasn't any dust to speak of, nothing looks like it burned up. This was one I bought from drives marketing division of Toshiba, so I don't have much $ tied up in it. As for operating conditions it was warm to hot in the shop, prolly in the 90's, the vfd is located on a shelf below and to the left of the grinder. There was a Box fan blowing from the left to the right.

WS
 
I had that happen once...had a fan blowing across it...and it popped. Usually that pop is from an internal fuse. Find the fuse and replace it.
 
That pop was a little louder than you're letting on wasn't it? I know because I had a Toshiba VFS7S do the exact same thing to me. I looked inside and couldn't find a fuse to replace. Nor could I visually find anything that would explain the loud noise like a failed capacitor or something. I suspect one of the transistor packs mounted to the heat sink failed catastrophically, but can't swear to it. I was amazed that there wasn't very much dust inside mine when I took it apart, but a short circuit doesn't take a lot it appears. Mine made a bright flash when it popped as well! I probably got mine at the same deal you did straight from Toshiba a year and a half ago or so (thanks Phil).

I did lots of research on getting it fixed and finally realized that a NEMA 1 VFD just wasn't made for the environment we're using the VFS7S in.

I finally bit the bullet and bought a pair of the KB Electronics NEMA 4 VFDs that Rob Frink sells for my KMG grinders and haven't regretted it since. I'll tell you that I'm a smart shopper and did an ass load of research and Rob seems to be very competitive with his pricing and has put enough of these NEMA 4 VFDs in the field to know they work. I seem to recall that they were just under $500.00 each shipped which was as good as the best price I found after shoping for two weeks and calling electrical suppliers far and near. NEMA 4 VFDs are not that common and usually they are quite a bit more expensive than Rob sells the KB Penta Drives for.

Besides, he's a hell of a guy and supports these forums and deserves your business.

I've still got my blown Toshiba sitting on a shelf. If anyone comes up with a cheap repair, I could find another use for it outside my grinding area.
 
I'll second what John has said - the KB Penta Drive is awesome...in AC or DC. :thumbup:
 
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