Best/Inexpensive DC Power Supply

If you go the battery and charger route, make sure the charger you use is actually a battery maintainer - one intended to put on vehicles in storage. They are set up to maintain a full charge battery without overcharging and boiling out electrolyte. Also keep in mind that a charging battery emits flammable gasses - this may present a fire hazard - especially if you weld or cut, or even grind metal nearby. I'd suggest the switching power supply - about $30 and you will be set and not have to worry about the battery. Something like this one would be plenty, especially since the load will be intermittent. An old battery charger with the start or boost mode might work as well -
 
Idea #1
Car battery w/ trickle charger.

Idea #2
Electric motor to run cars alternator, will require the battery to excite the field.
A Permininate Magnet Generator (PMG) would be best in this case but not sure if they come in low enough voltages or current ratings.

Idea #3
If you have a Variac in your shop then just build yourself a variable DC power supply. You just need a full bridge rectifier.
The 50 amp / 1000 volt model is $5 on this site. Be sure to mout the rectifier to a heat sink.
You can put a capacitor across the output to smooth the ripple but I don't forsee you needing that for this application.

http://www.myshopkart.net/blacksonline/product_info.php?products_id=49792919&



Just a couple thoughts.

I've built #3 to test some DC motors with.
 
Thanks to everyone for the list of ideas. I did find a 10 amp battery charger stashed away in my junk. Hooked it up and it did move the head up and down although the gear motor struggled a bit more raising the head. Could be the motor would run better if it was fed more amps.

I also have a PC power supply I'm planning on using. I've got another thread going on this as I'm not at all electrically or electronically inclined. The power supply is rated at 20 amps. Hopefully it will work better than the battery charger.

Tom S
 
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