Stepper Motor type???

I have got myself two identical stepper motor from a large printer and just wondered if anyone has any info on them.
The label is as follows:
--------------------------
Stepping Motor
type: 2878-9012
1.8d/step
Rw=75R

ORIENTAL MOTOR
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The motor have 5 leads in this order:
White
Green
Red
Brown
Black

I assume that one is common and the others are coils.
Does anyone know if common should be V+ or Grd.?
Thanks.


 

Common is always to ground.
the 4 others wires are for the two coils, for phase 'A' and 'B'.

The ground is easy to find since it's normally connected to the body of the motor.
Then you get 2 wires for each phase coil. You can find pair using a simple ohmeter.

J-P

Most of the schmatics I have seen and the way I run the steppers I have is Common is Positive and the Stepper driver grounds the coils in sequence.

Well....

I first tought that we where talking about a BIPOLAR step motor.

If it's not the case then charliem is right. You can also have a look at picaxe manual 3. It explain how to interface both type of stepper motor.

J-P

A few clues to steppers...

4 wire steppers are always used in bipolar mode
5 wire steppers are always unipolar
6 and 8 wire steppers can be set up for either uniploar or bipolar modes (just ignore the commons on a 6 wire for bipolar mode)

uniploar steppers can be used with the common either + or - . They are often used as the common as ground because npn or n-junction transistor drivers are cheaper than pnp or p-junction transistors.

In addition, it is usually safer, as the coils won't turn on if the controller fails.

Ok s if I try and find the pairs that should also tell me which one common is (the one left) right?

Also am I correct in assuming that the current goes from common to the high coil, or does it go from low coil to high coil?
I ask this because it works without a common.
Thanks,
Lliam.

 

To find the common on a a 5 wire device you look for the wire that has an equal resistance when connected to any of the other 4 wires.

If the resistance changes when you connect to any other wire it is not the common, as the coils should all be the same resistance from the common wire.

probably the white or the black....