[spideranne]

My office is having an auction on old computers. I think I remember reading that people us computer power supplies to power their props. I'm not planning on building anything animated this year, but I was thinking maybe I should start hording for the future. I could probably win a bid on any of these for about $2-$10. Is that worth it? Are any of these better then another for prop purposes?

Optiplex GX200 PIII 866 MHz
Optiplex GX110 PIII 733 MHz
Optiplex GX1 PIII 600 MHz
Optiplex GX1 PII 350 MHz
Optiplex GX1 PII 400 MHz
Optiplex G1 PII 350 MHz
Optiplex G1 PII 600 MHz
Compaq DSDT PIII 733 MHz
Clone PII 300 MHz
Dimension XPS PII 266 MHz

 

[DeathTouch]

Any of the power supplies in these computers would work.

 

[krough]

And once you get them, here is how to use them

http://www.scary-terry.com/atxps/atxps.htm

 

[jim6918]

Just rigged up a 400 watt PS from old computer to power wiper motor in witches cauldron. Used the 5 VDC side, and cut off unneeded connectors. saved the 12VDC lead in case i need is someplace else. Nice thing about computer power supplies is the relative high amp output. Bad thing is their size. Unlike wal-warts, they are pretty big and need to be concealed in the project. I get mine for free from computers scrapped by my office. Just make sure that the fan is working properly, or you will get some unwanted squeal.

 

[Wildomar]

Okay this is an area I am just delving into. I am in the process of trying to power up a wiper motor using a Computer Power Supply. But I noticed last night that the motor gets very warm/hot to the touch. I guess I was surprised how warm it got. Is this typical?

 

[spideranne]

Well I ended up with the winning bid on 4 Optiplex GX1 PII 350 MHz and 2 Clone PII 300 MHz. My total cost $6, a buck each. Thanks for the info on how to use them. I'll be saving these for next year as I vowed that I would only take on static props this year.

 

[DeathTouch]

Okay this is an area I am just delving into. I am in the process of trying to power up a wiper motor using a Computer Power Supply. But I noticed last night that the motor gets very warm/hot to the touch. I guess I was surprised how warm it got. Is this typical?

I have not run mine alot, but I would think that is ok. A motor that runs alot that sucks up a lot of juice has to get rid of the heat some way.

 

[krough]

I have used computer power supplies for the last few years for powering various DC motors. No problems yet.
Regarding heat, Ive never had a problem.

 

[roadkill]

Okay this is an area I am just delving into. I am in the process of trying to power up a wiper motor using a Computer Power Supply. But I noticed last night that the motor gets very warm/hot to the touch. I guess I was surprised how warm it got. Is this typical?

That would completely depend on your situation.

I have used wiper motors for a couple of years now - never once have I had one get more than slightly warm. If they are getting hot you might want to look at what kind of load they are working on (i.e. how much they are moving, lifting, pulling, etc as opposed to electrical load).

You may have them working too hard or straining.

I would also be curious how you have them rigged up. You said you are using a PS to run them - what voltage line did you use?

 

[roadkill]

... and cut off unneeded connectors. ...

I have to say this is a very bad idea Jim. First because you may want to use that PS for another prop some time - second because of cutting the lines you may inadvertently leave exposed hot leads which can pose a shock hazard.

IMO if you're not using certain leads then just leave them covered (I use hot glue) but leave the leads long in case you need them to drive another prop - or some low-voltage lighting - or something...

 

[roadkill]

Well I ended up with the winning bid on 4 Optiplex GX1 PII 350 MHz and 2 Clone PII 300 MHz. My total cost $6, a buck each. Thanks for the info on how to use them. I'll be saving these for next year as I vowed that I would only take on static props this year.

Congrats Spideranne!!! 6 bucks for 6 systems ain't too shabby. You might also want to check thrift stores, and the dustbins of the computer repair shops nearby. A surprisingly large number of computer PS get tossed with the cases.

Also check with your local freecycle.

Wiring and all is very easy once you've taken a look at what you have. I've only had one or two that made me scratch my head for a moment.

 

[Wildomar]

My apologies, I should have said that was un-loaded (no strain). I started with the the 12 V on the High RPM setting and just let it run to see if all was well. After running approximately 20 minutes I placed my hand on the motor body and felt considerable heat (could not keep hand there). I placed my hand on the PS and didnt feel any heat at all. Is there some sort of magic to setting up the PS to run the saturn wiper motor that I missed along the way?

I ran a jumper between the "PS On" post and a "common" (based on Scary Terrys PS Schematic) to turn the PS on since without that it wouldnt work at all.

Okay, I know in this situation Heat=Bad.... what did I miss along the way?

Any help would be great, Thanks.

 

[roadkill]

Try connecting to the low-power side of the motor. And use something like the 5 or 3.3 V lines since you are going to have a way fast prop using the 12V line. See if that doesn't help.

Also take a look at your operating situation. Is there air around your motor or is it enclosed?

I have used wiper motors with the 3.3VDC line on the LOW pins to get approximately 6 RPM (FCG speed).

 

[Wildomar]

All right I will give it a shot. I take it then, my set up (as best as I could explain) sounds correct?

I am planning on using it to tilt an upright coffin and also have the door open and close slightly. It may be that under this load the poor motor will take a dump if I cant get the heat down a bit.

 

[jim6918]

Yes, Roadkill, one should always exercise care working around electricity, thanks for pointing out my abreviated version of the process. However, relying on scary-terry's excellent web page, I did the following: jumpered one common and the green power on lead, soldered and heat shrinked. I then cut off unneeded voltage leads so close to the circuit board as to be no short cuircuit threat (+3.3, & -12 V), I then soldered quick-disconnects on the ends of all hot and common leads, then heat shrinked the ends of every unneeded lead (some 5 VDC and the 12 VDC for future use)the only thing coming out of the ps case is a single 5 VDC and a common lead. Since I have pracitally a never ending supply of surplus power supplies, I am not worried about getting another one for some other use.

 

[Wildomar]

Roadkill, I forgot to add that this test was conducted with the motor sitting out in the open so it was being completely exposed to cool August nights in southern California. Warm, but not enough to explain the heat the motor was producing. I will try the other settings and see if there is a change in temperature.

 

[roadkill]

All right I will give it a shot. I take it then, my set up (as best as I could explain) sounds correct?

I am planning on using it to tilt an upright coffin and also have the door open and close slightly. It may be that under this load the poor motor will take a dump if I cant get the heat down a bit.

I think the problem is trying to lift that coffin . Sounds like you're lifting way too much for that motor and straining it which will cause the heat.

 

[Wildomar]

I think the problem is trying to lift that coffin . Sounds like you're lifting way too much for that motor and straining it which will cause the heat.

Well actually it wasnt hooked up to anything yet, I was just letting the shaft spin freely as a test of my abilities to hook a Computer PS to a wiper motor. I was looking to see if something was going to short, shoot sparks, or just produce more heat than I was expecting.

As for the coffin, the plan is to have it just slightly out of balance so the motor olny has to overcome a fraction of the coffin's weight... well thats the plan at least.

 

[roadkill]

I would suggest a linear actuator motor - much like for a car window - instead. Much higher torque ratings - they operate quite a bit slower - but would be able to lift your coffin with no problem. Barring that you might want to look at www.meci.com for some other motor options. Some of these are still strong DC motors but you might want to consider using an AC motor for this application.

Back to the topic at hand, however.

If your wiper motor is getting hot like it is with NO load - then I would suspect there is something wrong here. It doesn't seem to be your connections (can't say for sure since I cannot see it) but so long as you followed Terry's diagrams you should be just fine. If that motor is heating up this significantly I'd find another motor.

 

[Wildomar]

Hey, thats a great website, thanks. I have another motor and will try plugging that in and see if I have a different response. Appreciate the help.