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Power supply for small 12v motors

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  • Power supply for small 12v motors

    I have a few small DC 12 volt motors, things like car window motors and such. I would like to know if there are some cheap and simple power supplies to run these things.

    Also, is there some kind of potentiometer which could control the speed. As you can see, I know little about electricity, so helpful ideas would be more appreciated than criticism.
    Vitَria, Brazil

  • #2
    Something like this would work.

    https://www.ebay.com/itm/DC-10-55V-M...Cclp%3A2334524

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    • #3
      Don"t have to spend alot of money on this, just find an old computor and use the power supply from it. I did this on my mini mill feed motor and cost me nothing but the time to get power supply out of the computor box. You will find more than one 12v supplies I used a second for a ring light.
      John From Slinger, Wisconsin

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      • #4
        find an old computer and use the power supply from it.
        I was going to suggest this, but then saw

        I know little about electricity
        and thought, "no". You usually have to put a dummy load on the 5 V part of the supply to get the thing to work, and the PWM suggested by Stu is still missing. For someone who is not an electronics tinkerer, an off the shelf solution is more appropriate. Unless learning that stuff is part of the project.
        "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

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        • #5
          The eBay controller is nice, but still needs a DC input, for which the PC power supply would do nicely. Then there's the issue of how much power you would want out of the motors you have. The controller would be no problem at 40A, but the DC supply would have to be up to it.

          I've farted around with PC supplies and haven't had to load the 5V. I have heard that it is sometimes necessary.

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          • #6
            Originally posted by Bob Engelhardt View Post
            The eBay controller is nice, but still needs a DC input, for which the PC power supply would do nicely. Then there's the issue of how much power you would want out of the motors you have. The controller would be no problem at 40A, but the DC supply would have to be up to it.

            I've farted around with PC supplies and haven't had to load the 5V. I have heard that it is sometimes necessary.
            5v Dummy load is needed with prehistoric pc power supplies. Most power supplies since Pentium 4 era wont need it(P4 was introduced 20 years ago)
            Location: Helsinki, Finland, Europe

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            • #7
              So it sounds like I could couple a PC power supply with the controller from eBay already mentioned and get something useful but cheap. Am I missing something here?
              Vitَria, Brazil

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              • #8
                5v Dummy load is needed with prehistoric pc power supplies.
                I guess I've identified the ones I've messed with then!
                "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

                Comment


                • #9
                  Originally posted by davidwdyer View Post
                  So it sounds like I could couple a PC power supply with the controller from eBay already mentioned and get something useful but cheap. Am I missing something here?
                  No, you've got it right. But you won't need to couple two together.

                  A quick check shows that even on a 400 watt supply that the +12 side is good for up to 20 amps. For light loads the motors should not stress that sort of use. But if you're worried about that then go with more like a 550 or 600W supply where I see the +12v output listed at up around 50 to 60 amps. Then for sure you'll be fine.

                  But if you would need to buy both the control unit shown off ebay AND the computer supply from scratch then you might find it simpler to spend a little more and buy one of these....

                  https://www.ebay.com/itm/Adjustable-...Cclp%3A2334524
                  Chilliwack BC, Canada

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                  • #10
                    [QUOTE=BCRider;n1911493]

                    No, you've got it right. But you won't need to couple two together.

                    But if you would need to buy both the control unit shown off ebay AND the computer supply from scratch then you might find it simpler to spend a little more and buy one of these [url]https://www.ebay.com/itm/Adjustable-Power-Supply-30V-10A-110V-/QUOTE]

                    That is what I use to power my window screen wiper motor driven mill table feed. Rarely takes more than 2 amps at 14 volts, more often than not I'm running six or seven volts at 1.5 amps.

                    Though I do wind it up to 30 volts for fast traverse without any problems. Those wiper motors are very robust !
                    Best Regards:
                    Baron J

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                    • #11
                      I have one of these and it works great.

                      https://www.wish.com/product/5c949de...59ce?share=web

                      Just plug the PC power supply into this and you're done.


                      John Titor, when are you.

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                      • #12
                        That link is corrupted with malware........
                        1601 2137 5683 1002 1437

                        Keep eye on ball.
                        Hashim Khan

                        If you look closely at a digital signal, you find out it is really analog......

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                        • #13
                          Originally posted by J Tiers View Post
                          That link is corrupted with malware........
                          Yep.

                          -js
                          There are no stupid questions. But there are lots of stupid answers. This is the internet.

                          Location: SF Bay Area

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                          • #14
                            You have a 12 VDC motor and want to power it. The first thing to do is find out the amount of current needed. To do that, I would suggest that you need to get a VOM (Volt-Ohm Meter). There are many inexpensive ones available, often at home supply stores like Home Depot but you can also get them from many sources on the web. Get one that has a 10 or 20 Amp. DC current scale. I recently purchased both a digital meter and two analog ones (Simpson 260s). The Simpsons are very good analog meters and would be an excellent choice for a first meter. They are somewhat expensive new, but many, many are available on E-bay for around $50.

                            You can use the meter with a 12 V (auto) battery to run the motor to measure the current. The test circuit would be a series connection: be sure you are using the highest current scale on the meter;
                            one wire from battery(-) to meter(-),
                            second wire from meter(+) to motor(-),
                            third wire from motor(+) to battery(+).
                            With that connection the motor should run and you can read the current on the meter. If you get a very low reading on the meter, you can switch to a lower current scale and try again. But always start with the highest current scale to avoid damage to the meter.

                            But be aware, this will only measure the no-load current and a motor can draw a lot more current when it has a load on it. It would be best to measure the current with the motor installed in whatever you want to use it in. If you can not do that, I would suggest that you use a current that is 2X or 3X the measured current. Or even more!

                            Once you know the current needed, there are many, many sources for DC power supplies and motor controllers. You could go to the electronic supply houses, but E-bay would be a much less expensive choice. Look for something rated for 12 VDC and at least the current you measured.

                            For speed control you will need a motor controller. There are many types: you want one that is for DC and is rated for the Voltage and current needed for your motor. You probably want one that uses pulse control. A pot (variable resistor) can control the speed of a DC motor after a fashion, but you will have low torque at low speeds. A pulse control will allow much higher torques at low speeds. Many of the low cost DC motor controllers on E-bay and other web sources are this type and they need not be expensive.

                            Some motor controllers may have the DC power supply built in. That would be ideal. Just look for one that has a 115VAC input. But if you choose a controller that does not, then you will need to buy a DC power supply. Again you need one that is rated for the output (motor) Voltage and current. Wall wart style supplies can be inexpensive and I have seen them with current ratings as high as 1 Amp and even 2 Amps. If you need more than that, you can search for what is needed on E-bay or I/we can provide other web sources.
                            Paul A.
                            SE Texas

                            Make it fit.
                            You can't win and there IS a penalty for trying!

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                            • #15
                              An adjustable Voltage power supply is not a very good way to control the speed of a DC motor. It may work, but I would hesitate on spending $60, PLUS shipping on something that may work or MAY not. Pulse style motor controllers are much better for DC motor speed control. Read my post above.



                              Originally posted by BCRider View Post

                              No, you've got it right. But you won't need to couple two together.

                              A quick check shows that even on a 400 watt supply that the +12 side is good for up to 20 amps. For light loads the motors should not stress that sort of use. But if you're worried about that then go with more like a 550 or 600W supply where I see the +12v output listed at up around 50 to 60 amps. Then for sure you'll be fine.

                              But if you would need to buy both the control unit shown off ebay AND the computer supply from scratch then you might find it simpler to spend a little more and buy one of these....

                              https://www.ebay.com/itm/Adjustable-...Cclp%3A2334524
                              Paul A.
                              SE Texas

                              Make it fit.
                              You can't win and there IS a penalty for trying!

                              Comment

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