How do I troubleshoot and rebuild these motors?

I have two motors part numbers 1057300 and 1057301 from an invacare motorized wheelchair that I wish to use in a robotics project. The stator turns easily, but barely runs when energized with a 24 VDC power supply. I have removed the electric brake. The motor hums when energized but barely moves. I suspect it could require new brushes - how do I trouble shoot this DC motor and if required, how do I know if it is worth rebuilding and how do I go about doing this?

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@rleaker bad brushes would not cause the motor to turn slowly. Are those still connected to the gearbox? Post some images of those motors with your question so we can see what you see. Use this guide Adding images to an existing question for that

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Hi,

These two images are from the service manual for an Invacare P9000. It uses the same motor part number as what you have stated.

Hopefully they will assist you in solving your problem.

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The resistance across both motor wires is reading 0 ohms. I looked at the brushes and they appear okay - springs are working too. I'll post a picture later today. Thanks for the tip on testing - not sure what it means though ... its odd that both motors are testing the same way. They were working when the chair was scrapped.

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Hi,

Not trying to be rude, but how good is your Ohmmeter? Looking at the pictures you posted it appears that you are using an analogue meter (no shame in that, I grew up on them) but if 0 ohms is a problem and 1-5 Ohms is good (according to the manual) then if your motor is 1 Ohm, is you meter accurate enough to pick it up? Try connecting a low Ohm value resistor(10-50 Ohms) in series with the motor winding (measure it first to ensure you know its true value, not its' marked value) and see if the reading matches 0 + the resistor or 1+ resistor (if you get what I mean) to see if the original 0 reading was correct.

Also, how much current are you capable of providing to the motor with your 24V supply? Is it the original battery supply from the wheelchair? If your motor is humming, it may not have enough current to create a large enough magnetic field to get it going.

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Hi! You are not being rude - I am a newbie to electronics so I'm learning as I go. My power supply is 250W total, each channel can supply about 3 amps and the motor is rated for 3.3 amps max so it should be adequate. I'll try the resistor trick, otherwise, I'll pick up a multi-meter for about $30. Thanks for getting back to me!

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Hi, Did you also put the brushes back into the same holders and with the same orientation as they came out? Take note of the last sentence in the Motor Brush Inspection section in the second image I posted, regarding having to be burnt in. The same would apply if you put them in a different brush holder or turned them over (although this last one not so much).

You also said that it barely moves when power is applied. Have you tried "helping it along" by spinning the shaft manually when the power is on to see if this helps to overcome the initial inertia. Be careful when you do this as it might suddenly take off on you. Ensure that the motor is securely tied down and that you have room to get your fingers/hand out of the way in case it does suddenly spin up.

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I did put them back exactly as I took them out - did not discount the power wires either. I'll try assisting them in the rotation ...

Thanks again.

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