Dc motor help

D

danny12

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Hello all,
I'm in need of some advice. I'm wondering if this motor https://www.ebay.com/itm/GW370-DC12...-Motor-1-250RPM/312823496892?var=611544362472 can be run with this PWM https://www.ebay.com/itm/0-100-Digi...2V-24V-36V-48V-Reversible-40A-US/124342951962 and powered by a 19volt laptop power supply.

I've checked the load I plan to drive with a torque wrench and get 5-8 kg cm It won't be used daily but when it is it will run for several hours. any other options would be greatly appricated
I need variable speed and reversing

Thanks
 
Looks like it might work. With no other data it is a "buy it and try it sort of thing". I need to book-mark the PWM controler link. Looks interesting. Hard to tell what current the motor will draw under load. Maybe an amp more or less based on the physical size/voltage? Probably figure in an extra 10-20% extra power for the PWM conversion for good margin. The laptop battery will likely have an amp-hour rating. The run time will depend on the current drawn by the PWM converter/motor combination times run-time. Probably never run the PWM at greater than 65% of full on because it will over-voltage a 12V motor.

Say the setup draws 0.75 Amps at the battery and your battery is 1 Amp-hour (1000mA-H) rated, it could run the motor for 1 Amp-Hour / 0.75 Amps = 1.33 Hours, approximately.
 
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The PWM controller is up to the task but I don't know about the motor. The listing states 10 kg-cm but for which motor? They offer ouput speeds from 1 rpm to 250 rpm. They will not all have the same output torque. If the stated torque is for the 250 rpm output, then you are OK. If it is for the 1 rpm output, you could have a problem.

While it us usually OK to overdrive a DC motor somewhat, you are looking at 60% over the rating. Using PWM, iy is possible to limit the average applied voltage by limiting the {WM to 60% and keep the motor within its power rating. There is additional stress on the insulation from the over voltage but it shouldn't be a problem for a 12 volt motor.

The motor current is also not specified. Nor do you specify the power supply current.
 
thanks all

im not sure about the laptop power supply amperage I'll need to dig it out and see.
what amperage do you think would be sufficient for that motor.

however if you have a suggestion for a power supply I'd surly appreciate it.
 
I had mis-read your original post. In my mind your power supply was laptop battery, not laptop power supply. Forget what I said about amp-hours and time running. Your power supply might be a good start depending on the current drawn by the motor/controller vs. the current rating of the power supply.

Maybe the ebay supplier will answer questions about the actual torque capacity of the motor at the various RPMs for you, to RJ's point. They may be able to tell you the full load current of the motor too. Do dig out your laptop power supply and share all the output ratings with us. Look for output voltage, output current and output power. From power you can get current if it is not labeled. Current = Power / Voltage.

Also, how many seconds or minutes at a time will you be running this motor? Many of those actuator motor/gear boxes are meant for rolling up a window, adjusting a mirror, etc. but are not meant to be run fully loaded for a long time.
 
One thing to keep in mind about DC motors, and their specs. is what happens when they are heavily loaded or stalled, and starting to move under load is a version of stalled. A laptop battery can be asked to deliver currents that need to be controlled, or you may experience the type of fire that cannot be put put out without it self restarting (Lithium).

The motor speed controller, if it is a good one, will have some built-in protection against short circuit loads (like a stalled motor). It's entirely possible the combination you have chosen is good for the purpose. I am just mentioning a design check extreme. Depending on the application, think about limit switches wired so the motor can drive itself out of them.
 
these are the two power supplies I have on hand
KIMG0467.JPGKIMG0466.JPG


this is the project I'm working on, their is very little load on the motor it is turning the center and moving the "carrage" no load on it. it's a mechanized sand blaster for 3/4 sch40 pipe. (cause I'm lazy).
16085932071481782739790412299981.jpg

thanks again
 
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