Electric motors - no specs

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#1
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A bit of surgery on an old inkjet printer on its way to be recycled, left me with two motors. A brushed DC one, and a bipolar stepper. A quick test with a 3V battery indicated that both motors work. Now the big question: with no marking (except the stepper is marked OKI), how to determine the appropriate operating voltage? Any smart tricks or tips out there? Increasing the voltage until something starts to smell funny is one approach, but I would prefer something slightly less destructive.

Knut

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Take a look at the electronics of the printer and try to reverse engineer the motor driver part. Or, better yet, reasemeble it and measure the voltages...

There are pointy haired bald people.
Time flies when you have a bad prescaler selected.

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You can 'ohm' the coils. Steppers come in nema sizes... if its a size 17 and others that size handle 20 watts, you can calc volts and amps given ohms and watts. I think.

Imagecraft compiler user

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Look through suppliers' web sites and catalogues and see if you can find similar motors. If the resistances etc. are similar you should be able to use the same voltages.

Leon

Leon Heller G1HSM

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Look at the power supply of the printer. One from it's output voltages supply motor.

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Thanks for the suggestions. I'll start off by measuring resistances and search a bit for similar looking devices. Reassembly is unfortunately not an option, and the power supply (built-in, ie. no connector labeled eg. 12VDC) is a bit problematic to "decode" since there are no markings on it.

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Plug it in and probe the collectors of the drive transistors?

Imagecraft compiler user

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Yeah, good idea, except the power supply is dead...

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Hi Knut.

If you know the printer make and model, how about googling for make/model spare parts? Just a thought.

You could also visit www.fixyourownprinter.com

Regards,

Ross McKenzie ValuSoft Melbourne Australia

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Thanks for the suggestion and the link, I'll check it out.

I started this thread partly because of the two actual parts in question; it would be nice to use them for something useful. But I also thought it would be interesting to know if there are som clever tricks out there that could improve the guesswork a bit. For example, many inexpensive motors intended for hobby/RC purposes have no markings at all (other than the box/plastic bag they come in when you purchase them).

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One of the things on my "to do list" is to investigate/test all of the old printer motors that seem to "sneak" into my spares bin (that one with the elastic sides :lol: ). Then I need to invent a "need" for them that will justify to "she who must be obeyed" why I am spending time and probably money on the activity. Gee it is getting hard to justify just having fun for the sake of it!

Ross McKenzie ValuSoft Melbourne Australia