Could this work as a cheap power supply?

[phantomcow2]

A regular DC motor controller? Surplus center sells one, input 110vAC and output 100vDC. The stepper drivers I am having built are looking like 100v input max. Rather than going and buying an actual DC power supply, could I just use this?
Assuming the voltage was lowered...

[NC Cams]

Yes and no.

Depends what you want to lower the voltage to

and,

Does it have the current you want/need

and,

Can you get documentation to facilitate doing the mods

and (perhaps most importantly)

Do you have the technical accumen to reverse engineer and then re-engineer a power supply adequately into the configuration you want???

If you can answer YES to all of the above, then the answer to your question is YES.

If you find yourself answering NO to one or several of the above questions (especially the "reverse engineering" one), then you might want to seriously consider taking another approach.....

or

Buy the P/S and use it as an electronics learning opportunity. IF you do that, start looking for documentation (IE: schematic for P/S) as this will be HUGELY valuable in re-engineering it into the configuration you want....

[H500]

I believe those controllers are PWM, unfiltered and very loosely regulated, so you would still need a filter capacitor and a fast diode. The circuit might dump out high voltage, so your stepper driver and components need to be tolerant to about 200v, to be safe.

[BobWarfield]

It hardly seems like you can get simpler than to buy a surplus toroidal transformer, bridge rectifier, and filter cap. Very little cost, easy to wire up point to point, and plenty of articles and postings on what's needed. I believe there is a nice white paper on it over on the GeckoDrive Yahoo forum, for example.

If you want something a little "sexier", both Tormach and Ajac CNC will sell you a little circuit board that ties everything together. Tormach wants more money, but theirs is slightly more complete. Ajax is $29 and it just bolts to the top of the capacitor. It has two screw terminals in for the AC and 2 out for the DC.

The transformers are easy to come by--www.partsexpress.com--among others. Go for it. DC supplies are straightforward.

Best,

BW