> Very nice work!. Imho look into a starting resistor before > you build a controller. You could ruin the motor without it. > A starting resistor will limit the torque at start. Take the > wire element from a 500W space heater and fold it in half 5 > times. Twist the resulting bundle and put it in series with > your existing cabling, with a second switch to short it. This > will limit start current to about 30 Amps (about 1Hp). If the > start is still to brutal cut wires from the strand and keep > trying. Eventually the wires will glow (ignore that but mind > anything that may catch fire from it). Normally the throttle > is arranged to make the main switch and as you push it > further make the start resistor shorting switch. I am sure > that you can make such a thing by bending the contacts on a > contactor a little and then using it manually (footably? ) > as a foot switch. > > Peter P. I remember seeing a very nice power control that rewired a set of small batteries (I think they were 6 volt Motor Cycle types) in different series and parallel combinations to provide from 6 to 48 volts over a series of steps. E.g. the first one was all the batteries in parallel so the result was 6volts at high amperage for starting out, then in parallel sets of 2 in series for 12 volts, and so on until all the batteries were in series for the maximum voltage. The advantage, so I remember reading, was that startup was smoother and a smaller starting resistor could be used. The mechanical design looked like a ships engine speed indicator system but with a set of knife switches built into it instead of the dial. It was break before make and there were detents so that it jerked from one position to the next in discrete steps. Building that might be an interesting project on its own, although you have to wonder if an electronic controller might actually be simpler... --- James. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist