[Cornelius3D]

I have a stepper motor I took out of a Lexmark Jetprinter 1020.

The motor is a Mitsumi M42SP-5.
I found the datasheet alright: http://www.mitsumi.co.jp/latest/Cata..._m42sp_5_e.pdf

What I can't figure out is what wire color is what? I have 5 wires, red, yellow, white, orange, blue - from left to right out of the motor. On the other connecting end the wires have switched. The white wire is now separated from the others, then to the right of that is : Red, Orange, Yellow, Blue. I think the designer of the circuit board organised the wires in a configuration that made sense to him as in grouping the A+- B+- .

Are the connections on the motors standard? If I look at the soldering on the tiny bit of board on the motor itself can I determine the wire configuration?
Are the plastic connectors to the board standard?

If someone knows what the wires are and can tell me that would be great.

For future reference tho, if I pull a motor out of a printer or scanner, how do I determine what the wire color configuration is?
Is there a way to figure this out? If I wire up a stepper to the wrong connections but stay within the working limits of the motor will I short out or break the motor?

[amishx64]

What I can't figure out is what wire color is what?

Get a multimeter, set it to measure ohms (< 200).
Draw 5 points on a paper in a pentagon layout and label each point a color. These correspond to wires.
Pick a random color wire and another random color. Measure the resistance. If there is a resistance, draw a line on the paper from one color to the other and write the resistance along the line.

After you have done all 25 combinations you will (should) clearly see that there are two main coils. The least resistance between each color wire is the ends of each coil. Since you have a 5-wire motor however, you are likely to have a wire attached to the middle of a coil, giving you half the coil resistance when you measure from that center wire. You won't have any use for this wire in any normal CNC application, so you will just leave it disconnected.

Are the connections on the motors standard? If I look at the soldering on the tiny bit of board on the motor itself can I determine the wire configuration?
Are the plastic connectors to the board standard?

No. It will most likely vary as per the manufacturer specs.

For future reference tho, if I pull a motor out of a printer or scanner, how do I determine what the wire color configuration is?

You could find the data sheet for the driver and trace the individual traces from the chip pins to the motor leads. It would actually be quicker to do the process I described above though.

Is there a way to figure this out? If I wire up a stepper to the wrong connections but stay within the working limits of the motor will I short out or break the motor?

You will not break the stepper as long as you stay within the constraints. However, since this is a 5-wire, you should theoretically halve everything for testing purposes. You won't break it though, trust me.

[amishx64]

Oh, and welcome to the Zone!

[Cornelius3D]

Oh, and welcome to the Zone!

Hey Amishx64,
Thanks very much for the welcome.
I had to buy a new multimeter so I am waiting on that. This brought up an entire new set of questions of course. With price range and functionality being all over the map. So I ended up getting this one. It seems to do everything I need.. right? lol

Sinometer DT9205 8-Function 32-Range Digital Multimeter by Sinometer [ame=http://www.amazon.com/dp/B0006FKF5Y/ref=cm_sw_r_tw_dp_LnE9qb17XPKQZ]Amazon.com: Sinometer DT9205 8-Function 32-Range Digital Multimeter: Everything Else[/ame] via @amazon

I will also follow up with images of the motor/wire color config.

[amishx64]

It seems to do everything I need.. right? lol

I will also follow up with images of the motor/wire color config.

It sure will.

I look forward to seeing the wiring diagram. If you have any questions, feel free to ask.

[Cornelius3D]

I got my multimeter today and promptly starting to go through the directions as you described.

Here is a picture of the motor: (the second image shows how the wires have changed order to connect to the circuit board.)


I turned the meter to Ohms 200. There isn't a setting for less than 200.
When I tested all the leads they were quite close in measurement.
Blue - Yellow : 137.5
Blue - Orange : 135.3
Blue - Red : 136.9

Yellow - Orange : 138.2
Yellow - Red : 139.9

Orange - Red : 138.0

Now when I tested them with the White wire that was separated from the bunch the numbers were much lower but there was a clear set of numbers high and low

White - Blue : 68.5
White - Yellow : 71.1
White - Orange : 68.5
White - Red : 70.3

These sets of numbers correlate well with the order they are in the connector which plugs into the circuit board.

So I thought this was the

The least resistance between each color wire is the ends of each coil.

Actually that part of your description I didn't really understand.
With the first set of numbers it would seem then that Orange and Red are the end of each coil. But how do I know which color is the other end. Is it Red - Blue or Red - Yellow?

Although looking at the second set of numbers it, and guessing with the order of the wires on the connector being Blue, Yellow, Orange, Red
the pairs would then be:

Blue : 68.5 & Yellow : 71.1
Orange : 68.5 & Red : 70.3

And the end then would be Blue and Orange.. but which ends? + or -
with a stepper motor it is A+- B+-


One thing I suddenly thought was about the red and black test leads of the multimeter. Will the measurement be different if I say test all the combinations with Red Lead:Blue Wire then test all the combinations with Black Lead:Blue Wire? I couldn't notice a big difference.

[Crevice Reamer]

Welcome to the Zone Cornelius.

One thing I suddenly thought was about the red and black test leads of the multimeter. Will the measurement be different if I say test all the combinations with Red Lead:Blue Wire then test all the combinations with Black Lead:Blue Wire? I couldn't notice a big difference.

For resistance or AC Voltage, it doesn't matter which way you place the multimeter leads. For DC Voltage though, black to negative, red to positive.

How Can I Determine My Stepper Motor Wiring Without the Stepper Motor Pinout? - National Instruments

CR.

[amishx64]

Sorry for the delay Cornelius3D.

I wrote the description under the impression that you had a bipolar stepper motor. This is not the case. You actually have a unipolar stepper motor where all the leads connect to a common.

Since you have a unipolar, there is no A+/- or B+/-

Here is a page detaining a circuit using a unipolar stepper.

Unipolar Stepper Motor Driver Circuit - Northwestern Mechatronics Wiki

Unipolar steppers traditionally aren't used in CNC applications, but that isn't to say that it can't be done.

[blitz355]

When measuring resistance it does not matter what color lead you place where. You will come out with the same readings.

When measuring voltage, switching leads may read as a negative voltage