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Electronics => Beginners => Topic started by: t1d on April 16, 2021, 02:28:38 pm

Title: Donor Stepper From Printer - What Voltage Does It Need? RG5-0765 Solved=12V
Post by: t1d on April 16, 2021, 02:28:38 pm
It came out of a HP 4L Laser Jet. Its model number is RG5-0765. I searched for it, but I didn't find the answer. Thanks for your help.
Title: Re: Donor Stepper From Printer - What Voltage Does It Need? RG5-0765
Post by: Kleinstein on April 16, 2021, 04:51:58 pm
For stepper motors the important parameter is usually the current, not so much the supply voltage. The normal way is to have the driver control the current. The supply voltage mainly sets the maximum speed. So at low speed some 3 V may be sufficient, while higher speed may need some 30 V.

The resistance and motor size can give an approximate value for the current - compare to other motors of similar size and look for comparable ohmic loss. So I²R is about constant for a given motor size.
Using slightly lower current is OK with reduced torque. 
Title: Re: Donor Stepper From Printer - What Voltage Does It Need? RG5-0765
Post by: thm_w on April 16, 2021, 11:27:18 pm
The part number is on the side of the motor "MSC..." if you google that you will find more information and some videos: https://www.google.com/search?client=firefox-b-d&q=mscm048a50 (https://www.google.com/search?client=firefox-b-d&q=mscm048a50)
Title: Re: Donor Stepper From Printer - What Voltage Does It Need? RG5-0765
Post by: JustMeHere on April 16, 2021, 11:45:56 pm
Do you have access to the printer?  Measure the power supply. 
Title: Re: Donor Stepper From Printer - What Voltage Does It Need? RG5-0765
Post by: ozcar on April 17, 2021, 02:31:41 am
Do you have access to the printer?  Measure the power supply.

I had a HP 4L for over 20 years (!). I still have the service manual for it (found it online somewhere, years ago, it must still be out there), and that indicates that the power for the "main motor" is 12V.
Title: Re: Donor Stepper From Printer - What Voltage Does It Need? RG5-0765
Post by: t1d on April 18, 2021, 12:58:33 pm
Thank you, so much, one and all, for your efforts to help me. And, a special salute to Ozcar, for the exact answer!
Title: Re: Donor Stepper From Printer - What Voltage Does It Need? RG5-0765 Solved=12V
Post by: Doctorandus_P on April 18, 2021, 01:53:26 pm
The first response from kleinstein is much better than the later response from Ozcar. Stepper motors usually have a driver IC to make the phase currents, and these work at the same time as a buck converter, and regulate the current through the motor coils.

Even if your motors power supply was 12V to begin with, if you just put 12Vdc on a motor winding, the motor is likely to fail. With a proper driver circuit however, the motor will run happily on an 24V power supply or even higher voltages (Depending on the driver IC used. Such IC's have a maximum input voltage).