Trox

Hi Kary, they are frequency controllers/converters who transform single phase current in to three phases and let you control all parameter on your motor. Like changing the hertz (frequency), that's adjust the speed on a AC motor. These are for sale on all places where they sell electronic components and of course Ebay. Look for the rating plate on your motor (small sign with Watt, amp and current), look for amp and current (110 or 230 Volts and amps). Make sure you buy a controller that is large enough, can handle the amp on your motor (and a bit more to be safe). I do not know if you live in a 230 or 110 environment. The instalation should be done by someone with knowledge of electronics. You could do it your self, then make sure you read up on the manual/instructions first (and be careful it's a lot of amps that can kill you). Could be difficult to understand these instructions if you have no experience with electronics. Every brand of controller have their unique set up, but the basically work the same way. Earth to earth from the motor to controller, the other three motor cables has to be changed around until the motor turns the right way (from motor to high current output controller). The two pole start swith (could be anything that are meant for 110 or 230 volt, like a lamp foot switch or something) are to be connected according to the manual. All motor parameters can then be controlled on the frequency controller, like speed startup time (how log until motor reach full speed in seconds) start up torque, and so on. You could also attach a pot meter to controlled the speed by (like a volum switch). Some says these controller are bad for the motor, but that's not proven to be right. It's a proven industrial solution used Daly all over the world to control every thing like AC driven fans and macines. Check your motor plate and buy a controller a bit larger than neccessary (by amps rating and the right volts) They only work by converting single Ph in to three phases, not single to single or three to three Ph. They are known to make motors sound bad on some frequencies, then just change the speed a little and it's gone (just the hertz that makes sound, nothing dangerous) You can buy a used controller that works fine too, have a look on Ebay. The bigger they are , the more expensive. These can be a little exepensive. Check it out and good luck. 

Tor