Stuff about VFDs and motors

[tonyfoale]

There has been interest in this topic recently, see http://www.homemadetools.net/forum/v...versions-73864

The content of this current post is contained in a PDF located at VFD stuff

Here are some pix as a trailer.

click image for full size

[DIYSwede]

-Good grief, Tony!
A diy-ed 3P yoke LC filter! Excellent approach.
Nice, straight-forward write-up very much appreciated at this receiving end!
Did you mention the cap values - I was a bit eager in reading it...

Is the transformer whine from inter-layer movement in the core laminations?
You could perhaps dunk the whole shebang in varnish?

Keep up the good work, and I'll be somewhat more patient in the future!

Tip: For designing filters, there's a bunch of RF designs that could be applicable even at these freqs:
Search "Butterworth LC filter design" or peek at this random find:
https://rf-tools.com/lc-filter/

ATB
Johan

[tonyfoale]

-Good grief, Tony!
A diy-ed 3P yoke LC filter! Excellent approach.
Nice, straight-forward write-up very much appreciated at this receiving end!
Did you mention the cap values - I was a bit eager in reading it...

You need to read a bit slower to get your answer.

Is the transformer whine from inter-layer movement in the core laminations?
You could perhaps dunk the whole shebang in varnish?
Johan.

I did dunk the core in varnish and that had no noticeable effect so it is probably mostly magnetostriction and there is not a lot that I can do about that. It really is not a problem, once it was mounted in a box on the wall I could not hear it.