[Kenwood] TS-930S fan

[David J. Windisch]

Somebody with what seems like a copyright fetish wrote that a-c-powered fans
can be slowed down with series non-electrolytic caps.

That's true as far as it goes.

There is a trap for the unwary.

About 45 years ago, I wanted a 24-hour clock for my shack.   I got one -- a
24vac one, measured its current draw, calculated the reactance necessary to
limit the current at 120vac, calculated the capacitance, came up with a
kluge combo of wax-covered caps from the junkboxes (remember those?),
slobbered the mess together, set the clock, plugged it in, wrote the time in
my log (remember those?) for 'my first 24-hr GMT QSO without having to
remember that 5PM EST is, umm, 2200Z, I think', and, some minutes into the
QSO, had to put out another one of my shack fires.    That clock was burning
electro-mechanical toast.

Seems that the capacitance tuned the thing close enough to series resonance
to make it draw a herd of current.

The 'new breed' of  low-voltage fans usually does not have a simple
induction motor, like my old clock, or like some of the 120vac fans (Rotron
comes to mind).   Series resistors are 'safer' with regard to current
limiting, when there's doubt about what's inside the fan.

To be safe, measure the current draw of whatever you put together before
making it permanent.

Hope this helps.

73, Dave, K3BHJ

Entire content uncopyright.   There are probably lotsa good reasons for
copyrights, but why, for simple 'Elmer-ing'?