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Running a small DC motor

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TimK

New Member
I have several small DC motors removed from Lexmark laser printers. They are used to feed the paper from the paper trays. The motors have 5 wires, (red, Blue, green, gray and white. The Red and Blue wires are attached to the motor the other three are attached to a optical reader on the end.

The motor seems to run using the red and blue wires using anything from about 3 - 24VDC.

I have not been able to find much information on the motors. (web searches) except sources to buy replacements.

Does anyone have instructions for circuits/programs for controlling this type of motor. Monitor/check speed, change rotation if possible.

Thanks
 

Grossel

Well-Known Member
It's not an DC motor, but rather a step motor. It demands a little more complex control circuit + two H-bridges in order to run.
 

Rajaneesh

Member
I have several small DC motors removed from Lexmark laser printers. They are used to feed the paper from the paper trays. The motors have 5 wires, (red, Blue, green, gray and white. The Red and Blue wires are attached to the motor the other three are attached to a optical reader on the end.

The motor seems to run using the red and blue wires using anything from about 3 - 24VDC.

I have not been able to find much information on the motors. (web searches) except sources to buy replacements.

Does anyone have instructions for circuits/programs for controlling this type of motor. Monitor/check speed, change rotation if possible.

Thanks



yes...its not an ordinary DC motor.... Cuz printer need the a precision movement for the feed tray, they have used stepper motors..... You may need a stepper driver to run this motor ......
 

TimK

New Member
I am not sure if it is a stepper motor. The Red and Blue wires look like they come from the motor itself the White,Green and gray wires come from an optical sensor on the end of the motor. Like I said I can run the motor by connecting the Red and Blue wires to DCV. However if I rotate the motor by hand it feels like a stepper motor.

Any simple ways to determine what it is.
Thanks
 

Rajaneesh

Member
I am not sure if it is a stepper motor. The Red and Blue wires look like they come from the motor itself the White,Green and gray wires come from an optical sensor on the end of the motor. Like I said I can run the motor by connecting the Red and Blue wires to DCV. However if I rotate the motor by hand it feels like a stepper motor.

Any simple ways to determine what it is.
Thanks


It should be a 5 wire unipolar stepper motor. attached here is the typical type.... You will have four phase and one common wire which should go to the +....

You can check it with an digital multi meter in ohm mode.....Between each phase and common , it should show equal resistance....
 

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mneary

New Member
It should be a 5 wire unipolar stepper motor. attached here is the typical type.... You will have four phase and one common wire which should go to the +....

You can check it with an digital multi meter in ohm mode.....Between each phase and common , it should show equal resistance....
Please explain how TimK has made a 'stepper' motor run just by connecting red and blue to plain DC.

@TimK: The reason it cogs like a stepper is that the magnets are strong and the rotor poles don't overlap. This isn't a problem unless you need smooth rotation. Your options for controlling the DC really depend on your application.

To determine the sensor operation, set a multimeter to the diode check setting. One pair of wires should look like a diode with a forward voltage between 1 and 1.5 volts. This is the emitter (LED). Its cathode is probably intended to be grounded. The third wire would be the collector of a phototransistor (with its emitter to be grounded.).

Supply the sensor's LED with about 5mA (1k resistor to 5V). Pull up the phototransistor with a 10k resistor to +5V. As each opening in the tachometer wheel passes the detector, the voltage should go low. Put a tape flag on the shaft and turn the motor one full rotation. You now know how many slots are in the detector wheel.
 
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shortbus=

Well-Known Member
Most Helpful Member
Aren't these motors a form of brushless DC motors? The older style printers did use steppers but in the late 1990's the paper feed changed to BLDC motors. The sensor (chopper wheel) on the end of the motor was to cut power after so many steps to control position of the paper.
 

TimK

New Member
Thanks Guys
This makes sense, They seem to be a fairly strong little motor. I am sure I will find something to do with them.

Happy Holidays
 

mneary

New Member
If it's a BLDC it should not run backwards when the power is reversed. Beware this could also destroy the control circuit.
 
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