# computer power supplies



## spideranne (Jul 17, 2006)

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


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## DeathTouch (Sep 6, 2005)

Any of the power supplies in these computers would work.


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## krough (Oct 7, 2004)

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

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


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## jim6918 (Aug 18, 2006)

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.


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## Wildomar (Aug 30, 2006)

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?


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## spideranne (Jul 17, 2006)

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.


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## DeathTouch (Sep 6, 2005)

Wildomar said:


> 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.


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## krough (Oct 7, 2004)

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.


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## roadkill (May 11, 2006)

Wildomar said:


> 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?


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## roadkill (May 11, 2006)

jim6918 said:


> ... 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...


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## roadkill (May 11, 2006)

spideranne said:


> 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.


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## Wildomar (Aug 30, 2006)

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.


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## roadkill (May 11, 2006)

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).


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## Wildomar (Aug 30, 2006)

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.


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## jim6918 (Aug 18, 2006)

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.


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## Wildomar (Aug 30, 2006)

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.


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## roadkill (May 11, 2006)

Wildomar said:


> 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.


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## Wildomar (Aug 30, 2006)

roadkill said:


> 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.


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## roadkill (May 11, 2006)

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.


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## Wildomar (Aug 30, 2006)

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.


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## .id. (Jul 3, 2006)

Wildomar, out of curiosity, have you tried running on the low speed setting of the motor? Did it get hot on that setting too?


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## Wildomar (Aug 30, 2006)

I was going to do that last night, but some relatives stopped by and I couldnt figure out how to gracefully excuse myself to the garage. I will try tonight.


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## Michigal (Jan 3, 2006)

roadkill said:


> 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, can you elaborate a bit on using a PS on low voltage lights? I have a set of low-voltage spotlights I got for free but without the transformer (got the wire). I'd like to use these, since I just acquired a PS for a box of Ring Dings, but am unsure which voltage to use. I never thought of it for that purpose, but it'd be great if that would work.


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## Wildomar (Aug 30, 2006)

.id. said:


> Wildomar, out of curiosity, have you tried running on the low speed setting of the motor? Did it get hot on that setting too?


Okay, I tried out the motor on the low setting with no load, sitting wide open on the work bench at 12V and 5V - same thing occurs. Also this time, I monitored the heat progression checking it every few minutes to see if it was instantaneously hot or a gradual thing. Well, it is actually very gradual.

So what does this mean? Heck if I know. I am wondering if the gearing is somehow set too hard or binding since the heat is gradual. Although there is no audible sound that leads me to that query. If it were electrical I would expect a rapid heat exchange... Agree, disagree? There is an inset screw at the top ofthe motor, is that an adjustment of some kind?

Thanks,
Chris


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## Wildomar (Aug 30, 2006)

madmax said:


> Go out to your car and run the wipers for 10 Min's, then pop the hood and touch your wiper motor......it will be hot.


I can't mine are vacuum operated. 

Thats good to hear though, since I realized the heat came on gradually,I was less concerned, but then I started wonder at what point does it level off?


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## mrklaw (Nov 11, 2005)

Is the wiper motor connector you are using look like this?









If so, I would not use the high rpm setting (applying power connectors to low and high pins) because it draws a lot of current and the motor isn't designed to be run like that for long periods (if at all). I hooked up 5v from my pc power supply to the low and common pins so the movement wouldn't be too fast and it doesn't get too warm.


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## Wildomar (Aug 30, 2006)

mrklaw said:


> Is the wiper motor connector you are using look like this?


Yup, that's it. Yeah I saw recently that Scary Terry had suggested not using the 106 RPM setting (High/Low) hookups so I was going to shy away from it, especially now given the heat mine produces.


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## roadkill (May 11, 2006)

Michigal said:


> Roadkill, can you elaborate a bit on using a PS on low voltage lights? I have a set of low-voltage spotlights I got for free but without the transformer (got the wire). I'd like to use these, since I just acquired a PS for a box of Ring Dings, but am unsure which voltage to use. I never thought of it for that purpose, but it'd be great if that would work.


With a PS you have 3 voltages to choose from - 3.3V, 5VDC, and +/- 12 VDC. They all have various amperages (highest is on the 3.3 VDC line IIRC).

You can take the 3.3VDC line and use that to drive some low voltage lights (this would hardly get but a dim glow from a nightlight). You can also use the 5VDC line(s) do power these lights. You'd have a dim but usable light.

Most likely you have low-wattage lights which is very different. Even though they may only require 4W they are still using 120V in many cases. Please check the input voltage requirements. If it is actually low voltage then you should be good-to-go. Just connect the 5VDC line to one lead (assuming these spots are being run in parallel off one continuous main line) and find a common and hook that to the other lead for your spots.

I was really thinking more of low voltage lights for immediate use with a prop being driven with a motor or such off the same PS. I don't know if I've adequately explained what I was thinking but I hope I have.


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## Wildomar (Aug 30, 2006)

Since the 12V is readily available off of a Computer PS, I was going to use automotive tail light bulbs to highlight certain projects since cars are predominantly 12 volt systems. No to mention bulbs come in a huge amount of sizes.


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## mrklaw (Nov 11, 2005)

LEDs would be great for this also and they don't use much current. Most LEDs that you buy off of ebay come with resistors for 12 volts anyway.


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## Michigal (Jan 3, 2006)

roadkill said:


> .
> 
> Most likely you have low-wattage lights which is very different. Even though they may only require 4W they are still using 120V in many cases. Please check the input voltage requirements. If it is actually low voltage then you should be good-to-go.
> 
> I was really thinking more of low voltage lights for immediate use with a prop being driven with a motor or such off the same PS. I don't know if I've adequately explained what I was thinking but I hope I have.


Thanks for the reply, roadkill. I will unearth them from my cellar and see just exactly what they are. But my gut feeling is that they probably are just the low wattage. Too bad, since I'm rearranging the display this year, and could have used the extra low light spots.


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## JustMatt (Jul 13, 2006)

Wildomar - no, that may not be normal. Is is possible that you are overloading the motor, like using the 12v wires on a 6v motor, possibly?


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## Wildomar (Aug 30, 2006)

JustMatt said:


> Wildomar - no, that may not be normal. Is is possible that you are overloading the motor, like using the 12v wires on a 6v motor, possibly?


I understand what you are saying, but that shouldnt be the case here unless A) something is wrong with the motor internally; B) something is wrong with the Power Supply; or C) I have miswired.

If A is the culprit I dont know where the problem is yet (still looking). The motor is a 12 Volt Automotive Winshield Wiper Motor so the 12 Volt power supply should be perfectly fine... I need to double check it with my Multimeter but have not done so yet. But since I have run it at 5 volts and the same thing occurs, I would surmise my problem is with the motor either mechanically or electrically. Although I am leaning toward a mechanical problem and it is causing the motor to work too hard. Well see. Thanks for the input!

By the way!! DING DING DING! Just had a thought, folks. I tried to run the motor using the 3.3 Volt set up and it barely moved (1/16 of a revolution before stopping). And for some reason I thought I remember someone saying that it is possible to run it on 3.3 but it really wont have the torque to do much. If mine doesnt have the power to even turn with nothing hooked up would that suggest internal binding? Have other people been able to get theirs to run on 3.3?

Thanks


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## mrklaw (Nov 11, 2005)

My first motor (a 13rpm AC motor) that I bought for an FCG didn't run very well and I opened it up and it had a bunch of grease in the gears that had hardened up. After I picked it out, it ran better but tended to run hot.


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## JustMatt (Jul 13, 2006)

I know this is an older thread but I thought I'd post a coouple of links I found today (in addition to Scary Terry's link earlier) in case anyone is looking:

http://www.directron.com/2powersupplies.html
http://www.antennex.com/preview/archive3/powers.htm


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