[keebler303]

I recently bought an old rockwell porta band. It has adjustable speed but the circuit board no longer works and someone has bypassed it altogether. I would like to make a new unit so that I will have adjustable speed. Will a light dimmer do the trick to vary the voltage to the stator? I would stick in a triac but I'm not sure how to size the phase shifting resistor capacitor network I have heard about so that it fires symetrically.

Thanks in Advance
Matt

[Al_The_Man]

You will find alot of data on the Manufacturers web sites like IR, Freescale, Allegro etc.
You need to find out the max current load for the motor and size one accordingly, if the motor has a simple digital/pulse tach, there are series motor IC's than will give you stable speed control under load.
Al.

[keebler303]

Thanks Al

This is an old unit 60's or 70's probably. I am looking for a rather primitive design using only a potentiometer, a triac and a couple passives, For the mentioned IC's I would need to provide dc voltage and supporting components, correct?

Thanks
Matt

[Al_The_Man]

The basic Diac/Triac circuit is the simplest http://www.littelfuse.com/data/en/Ap...tes/AN1003.pdf
The PDF is the Motorola used in appliances.
Al.

[keebler303]

Thats just what I was looking for.

Thanks Again
Matt