Jack Erbes wrote:

Someone asked if this router speed control would be okay to use with a
typical non-variable speed 1/2" drill motor (5 Amps or so).:

http://www.mlcswoodworking.com/shops.../speedcon.html

I called to get a little more info and the seller says that it is for
use with "brush type motors of up to 15 Amps" and that it is a
"voltage sensitive device that maintains constant torque".

If I understand it right, this must do more than simply drop the
voltage. I wonder if this is like a VFD in that it can vary speed
without overheating the windings? Anyone want to venture a guess on
how this works?

I'm reluctant to tell someone to do something that might fry their
drill motor. If it works as they say, for $24 and free shipping, I
might get one myself.

-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

It should work fine with a brush type motor in a drill.

IIRC those speed controls sense the "generated" back EMF during the portions of each
half wave cycle when their controlling triac is "off" and use that voltage as a
feedback signal to help keep the motor at a constant speed in the face of varying
torque loads.

IIRI, someone please correct me...

FWIW, I picked up a similar appearing speed control device from HF when it went on sale
for less than $10 and it's worked well for me the few times I've used it on my router.

Jeff


--
Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"If you can keep smiling when things go wrong, you've thought of someone to place the
blame on."