What type of matching connector is that for the stepper

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  • June 9, 2011 at 9:57 am #1789
    Mark_H
    Member

    I am attempting to figure out what matching connector that I should use for the stepper connectors.

    June 9, 2011 at 3:38 pm #1790
    alden
    Member

    The motor connectors are the same as those used on the Reprap/ Makerbot electronics. They are 0.156″ Molex headers, Molex part #09-50-3041. These are just the shells. You also need the pins (“terminals”), which are Molex part #08-50-0134

    These can be found at Mouser Electronics:
    http://www.mouser.com:80/Search/ProductDetail.aspx?R=09-50-3041virtualkey53810000virtualkey538-09-50-3041
    http://www.mouser.com:80/Search/ProductDetail.aspx?R=08-50-0134virtualkey53810000virtualkey538-08-50-0134

    There are many other manufacturers that make and sell similar parts. They also sell (very expensive) crimping tools for these terminals, but I just use needle nose pliers to crimp the low volumes I need.

    Alden

    June 13, 2011 at 6:19 am #1791
    Mark_H
    Member

    Thanks for the response and I sure this will help others as well. I went searching through the molex product line trying to match the male connector and let me tell you that is enough to get lost for days with all the parts molex has.

    While I put searching for matching connectors aside for a bit. I went on to figure out my stepper motor coils. I came up with a slight different or maybe a bit more drawn out way to identify unknown coil pairs for a 6 wire unipolar stepper motors. The results were kind of interesting( more for someone with a background in electronics) but can be used by anyone who can check resistance, record the info, follow my steps for identifying the coils. For those who like to dabble in basic ohm’s law theory the data sort of shows a math puzzle but when ohm’s law is applied to that data, it suddenly makes sense. Not sure if anyone would be interested in seeing it but it helped me figure out what I had on those unknown unipolar motors.

    June 13, 2011 at 12:56 pm #1792
    alden
    Member

    Unraveling a motor without specs can be a challenge. I first always look for a data sheet by searching on the motor part#. It’s often on the motor, but not always. If I can’t find the data sheet it’s time for the ohmmeter.

    Wire colors can be clues. Green and black are often the outer leads to a winding, and red and blue also often go together. Sometimes there will be a solid colored lead and a striped lead of the same color. These also usually go together. In a 4 wire motor (bipolar winding) if you test these pairs and they come back with the same low impedance (e.g. 4.2 ohms for a big motor, 92 ohms for a small one) you are done. These are the two windings.

    In a 6 wire motor (unipolar winding) there will be an additional center-tap lead in between the outer leads. A white lead is often the center tap for the red / blue pair (red, white and blue), and a yellow lead is a center tap for the green / black pair. The ohmmeter will read 1/2 the resistance from the center to the outer leads. So if the resistance between the outer leads read 4.2 ohms, the resistance to the middle should be 2.1 ohms. I usually wire across the outer leads and leave the center alone (but insulated). I’m told you can also get higher torque (and consume more power) by running a unipolar just from the center to an outer, but I’ve never tried this (probably should).

    Sometimes you are lucky enough to find a 6 pin header on your motor (the wrong size for your application, of course). Test these for outer1-center1-outer1, outer2-center2-outer2.

    But don’t trust the colors and plug alone. I’m looking at a NEMA17 motor right now that’s 6 pin plug is wired green-black-yellow, red-blue-white. The colors are right, but the yellow and white center taps are not wired to the plug pinout the way I just described. Can’t be non-standard if there IS no standard.

    So always test with an ohmmeter.

    Mark, did you post your method somewhere?

    Alden

    June 13, 2011 at 4:06 pm #1793
    Mark_H
    Member

    That wire color tip was a good one. I haven’t had much time with steppers myself but have went to school for electronics, even though it has been awhile since I brushed it off.

    I haven’t posted the method anywhere yet, it did involve the ohm meter and spreadsheet mapping out the color pairs. I thought I might write up a tutorial or something so if you took a 6 wire motor and without knowing anything about it you could find out which one’s were paired. The fun part was how the data revealed that info. I think it would help others with less experience in the area, to be able sort out an unknown 6 wire stepper without relying on the wire colors conforming to any standard, should they run into that or just for the sake of learning.

    June 14, 2011 at 8:11 am #1794
    alden
    Member

    Here are some links I found by searching around that explain stepper basics and how to figure out what wire is what.

    http://www.reuk.co.uk/Examining-a-Stepper-Motor.htm
    http://digital.ni.com/public.nsf/allkb/0AEE7B9AD4B3E04186256ACE005D833B
    http://techref.massmind.org/techref/io/stepper/wires.asp#step2 (for 5 wire motors)

    Alden

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