David Chapman via EV wrote:
Working on a belt sander project using a 130V PMDC motor off a treadmill. The control
board got crushed so I need a simple cheap adjustable speed control. Anyone have
something laying around they want to get rid of? Need 115Vac input. Thanks Dach. "Do
what you can, with what you have, where you are" - Theodore Roosevelt “We reached
the old wolf in time to watch a fierce green fire dying in her eyes .... I was young
then, and full of trigger-itch; I thought that because fewer wolves meant more deer, that
no wolves would mean hunters’ paradise. But after seeing the green fire die, I sensed
that neither the wolf nor the mountain agreed with such a view.” - Aldo Leopold
How about an old-fashioned phase-control light dimmer? It will give you
variable speed, though not speed "control".
Or, steal the speed control out of an unused or garage-sale 120vac
drill. The circuit is only slightly more complicated, but uses the
motor's back-EMF to sort-of regulate the speed.
I'm looking at a circuit in the GE SCR manual 5th edition on page 293.
It uses a bridge rectifier, 1 SCR, 2 resistors, 1 potentiometer (the
speed control), 1 capacitor, and two diodes.
It is vanity to do with more that which can be done with less.
-- William of Ockham
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)