PWM or SCR Motor Controller?

[Mozencrath]

Hi all, I have been spending long hours trying to figure out the best controller for my application. I have a 12VDC 1/4hp Permanent Magnet motor that I need to build a speed controller for....It needs to be very simple but must be able to do one important thing: Provide good power/torque at very low volt/RPM. In other words, I need the motor to be able to run very slowly (100RPM~) but still draw significant amperage. Can I achieve this with a basic PWM controller using a 555 timer and a 2N3055? Any suggestions are appreciated or links.I have at my disposal:

Plenty of 2N3055 type transistors
LM317s
All types of pots, resistors and caps
Transformers

 

[duke37]

I have designed a circuit to drive a 12V DC motor for a coil winder. I have had some of this working but have added things which have not been tested. I am busy at the moment so this will have to wait.

It uses the back EMF of the motor to measure the speed and will give a pulse if it running too slow. It is driven by rectified AC without capacitor smoothing.
Forget the counter circuits