i went and built an extractor this winter, all sst constuction. now i am trying to come up with the best way to regulate the speed of it. right now i have a pair of pullys/shivs that reduce the rpm to about 325 max, but i have no way of ramping it up/down. i have been looking for a used vfd because they are so $$ but i was wondering if anyone had used a mechanical clutch to allow more speed control, and if so what kind and where could i get one?
I've seen many a mechanism that had the speed controled with a "belt tightener". Basically this is just an adjustment of a tigher or looser belt. I've seen them on printing presses and lawn mowers and extractors. Basically you just have lever that has the pulley mounted near the fulcrum end that when you push on the lever it tightens the belt. By engaging it slowly you cause it to "ramp up". You need some kind of an adjutment with a screw or something similar that pulls the lever over more or less to go from unengaged to fully engaged an anything in between.
It's simple in reality, but hard to describe.
Most folks use an old NON solid-state
"speed control", which is, in essence, a "light dimmer" that can handle lots
of current without burnhing up.
If you e-mail the specs on your motor
(Max amps, volts, phases, horsepower
whatever the nameplate and instruction
sheet says) I can hook you up with a
fellow in Lynchburg VA who is retiring,
and selling off his ham-radio gear, which happens to include a very beefy variactor.
Cheap too - he sold me a Tektonix 515A
Oscilloscope in mint condition for $15.00
(Worth several hundred, minimum).
My brother in-law is going to have a very
big, very heavy birthday present.
You could also use the disc drive like on the ground speed control for mowers, snowblowers etc. these are cheap and can be found at almost and power equipment dealer.
What Jim describes is what is on most extractors now days. Probably has less wear on it than a clutch would although everything wears out eventually.
thanks for all the help, i decided to get a new motor 220 as opposed to 110 because i can get vfd's for that notor cheeper. thanks again for the suggestions though.