PDA

View Full Version : power converter for 12 volt???



torker
11-06-2004, 01:47 PM
I'm thinking of using a windshield wiper motor for a feed motor on the quill on my mill. What would it take for a reliable power source for these motors? Thanks!
Russ
BTW...I want to use this for boring with a boring head on a m/d. Would like it to be variable speed also. Any ideas?

[This message has been edited by torker (edited 11-06-2004).]

Evan
11-06-2004, 02:30 PM
Your every day 250 watt computer power supply will put out +12 at ten or so amps. You need to put some load on the other outputs, just a couple of hundred milliamps will do. You also need to find an AT type supply from an old junker 'puter since they don't rely on power good signal to function. Got an old 486 lying around?

SJorgensen
11-06-2004, 04:33 PM
Or find a car battery charger. You might already have one in your garage just sitting there doing nothing. There is no reason not to make it earn its keep.

Forrest Addy
11-06-2004, 05:09 PM
I see 12 volt PWM motor controllers on eBay for $40 or so. They're intended for DC motor control but since they are PWM the control might be pretty good. Far btter than the old half wave SCR controls.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=26237&item=3850186726&rd=1&ssPageName=WDVW

hoffman
11-06-2004, 07:25 PM
What kind of mill? I also need a quill feed on my Gorton 1-22. Look at the pics on the yahoo Gorton site for some ideas.

PSD KEN
11-06-2004, 10:11 PM
I got a 550 watt, 24A,@12vdc off ebay for around $19.00

Mike Burdick
11-06-2004, 10:21 PM
Just a thought hereā€¦

What about using a variable speed drill? They have high torque (low end) and one could replace the trigger switch with a knob rheostat to maintain the desired speed. Decent quality hand drills are fairly inexpensive now.

charlie coghill
11-06-2004, 10:49 PM
Also you might look at one of the elect screw driver drills.
I am going to make a table feed from one of the old 10ft. dish antenna positioners, they operate at 24 to 36 volts.
Charlie

torker
11-07-2004, 01:05 PM
Thanks for all the ideas you guys!
Evan....I do have an old 486 but I'm not sure what you mean,,,(electrical dummass!)
SJ...Was wondering about a charger but would it work as a constant supply source?
Forrest...Sorry but what is a PWM?
hoffman...It's for a mill/drill. I need the quill feed for boring. I've been using a 3" boring head in it and am not getting the finish I want doing it manually.
The screwdriver/drill idea might work also. I was digging around in my junk pile and found a power window motor that may work also...very easy to reverse and can be mounted in a good out of the way position.
Thanks again!
Russ

Evan
11-07-2004, 02:41 PM
Russ,

The power supply in the 486 will do what you need. You need to put a few resistors across the unused outputs. On the plus 5 and minus 5 volt put a 6 volt marker light bulb to ground. Ground is the black wires in the connection to the motherboard. On the -12 volt put a 12 volt marker light bulb to ground. The twelve volt connection is the yellow wire in the four wire harness that goes to all the drives in the system. Get out the volt meter.

SJorgensen
11-07-2004, 02:47 PM
Evan forgot that not everyone speaks "computerspeak."

Torker, when IBM released the "Personal Computer" specifications to the world we went through an evolution of the main processors and it went something like 286, 386, 386sx, 486, etc.

Since there are lots of these machines in the trashpiles you might find one with about 200-300watts of 12v from one of those.

torker
11-07-2004, 03:11 PM
Thanks again guys! Simple solution...I'll go see our computer tech who we use for our business. He'll fix me up I'm sure. I'll tell him what you said Evan and I'm sure he'll be able to drag something out of his junk pile.

torker
11-08-2004, 01:28 AM
Forrest...I got it...PWM= Pulse Width Modulation!