Model Forum / General / Railroads / May 2008

You don't mention current draw, nor what purpose the motor will be put
to.
If you just want to control the speed of (say) a windmill then you just
need an adjustable voltage. A simple $20- motor control kit and a "wall
wart" from an electronics shop will do the job.
(Google Jaycar)
Even a variable step/voltage wall wart would do the job.

If you want to control the speed of a tool under varying loads then
you'll want a "feed-back" type electronic controller.
Model railway controllers are for "driving" a vehicle where you need to
control speed, direction and position.

Regards,
Greg.P.

It's not clear from your question and data exactly what you are trying
to do. All of the devices you list will control the motor, assuming it
doesn't draw more than an amp or so. But that is not the end of the
story, as it's not clear just how precisely you want to control the
motor's speed.

All of the listed devices are "powerpacks". They produce constant power
at any given setting, by wasting some of the power so that less power
gets to the motor, which means the motor will run at a lower speed. But
as the load increases, amperage will increase, so that voltage will
decrease. That means the motor will slow down under load. If that's what
you want, any of the powerpacks listed will work.

However, what you may want is a constant voltage, variable power
controller, so that the motor will maintain its speed even when the load
increases. These  devices exist, but they cost a fair bit more than
powerpacks. DCC systems perform just this task, BTW, so you may want to
look into using one of those.

HTH