Re: [CAD_CAM_EDM_DRO] Re: LARGE DC MOTOR speed control question

Jon Elson wrote:

>
> STAN MCDONALD wrote:
> >
> > Do you have an idea on how to make a speed control besides a varac?

Live Steam Magazine, March 89, has a circut for driving 1-1/2 inch scale
model locomotives

>
> Yes. But, it is not for the amateur! A 3 Hp PWM variable speed DC
> drive would normally
> be done today with a big IGBT (Insulated Gate Bipolar Transistor).

Power Mos-fets are another way to go now. They can be parreled until
you get the current you need. The locomotive control was designed for a
24 volt source so you would to select higher voltage mos-fets.

> If you are not fairly confident of your abilities as an electronic
> circuit designer and
> power systems type, I would not attempt this! If you don't have an
> oscilloscope, forget it!

Building the Live Steam comtroller does not require much in the design
field but you should have some skills in using intigrated circuts.

John Grant