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Nema 23- 8 wire - why the motor getting so hot??

Discussion in 'General Electronics' started by EfrainLenisMaturano, Apr 15, 2017.

  1. EfrainLenisMaturano

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    Hi,

    I have a nema 23 connected to the board DB25-1205, this motor no has data sheet, only for a model 6 wire:
    • Nema 23 Kysan, 57BYGHM004-A
    • Step 0.9º
    • Relate Voltage 2.5 V
    • Current per phase 2.8A
    • Holding torque 10 Kg-cm
    Why over hot??
     
  2. Hunter Babich

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    Do you have this motor wired in series with another? Can you take an amperage reading between all the poles while it is running?
     
  3. EfrainLenisMaturano

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    Only have one motor trying. I will take amperage
     

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  4. Hunter Babich

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    This could be true. check your wiring diagram from the manufacturer. Definitely something in the wiring messed up.
     
  5. EfrainLenisMaturano

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    I
    I take reading amp at less 1.4A is good
     
  6. Carl W. Livingston

    Carl W. Livingston Well-Known
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    Hi,

    You say that you have an 8 wire motor. That means that there are 4 windings

    There are 4 windings for greater flexibility at the install.

    A 4 winding stepper motor can be configured three different configurations - Uni-polar, Series winding bi-polar and Parallel winding bi-polar.

    Uni-polar:
    Depending on the direction the windings are wound on the stator, with reference to each other, the two pairs of two winding can be configured for bi-polar. This is where each winding pairs are connected in series and, the common point or center node is connected to the power source. The opposing ends of the series pair are then connected to driver transistors that pull that end of a given opposing winding end to GND.

    This is repeated for the other series pair. The four windings and four drivers are then sequenced to give proper timing for direction. The orientation of which ends of the winding pairs connect together, making the center node is important. The net effect of incorrect winding pair orientation are, no stepper rotor motion, gibberish for rotor motion and, in both cases, lots of heat.

    Series winding bi-polar:
    With series winding bi-polar, two of the windings are connected in series for each pair. The series windings are then driven via an "H-Bridge"type driver - one for each series winding pair. The physical connections are important here because, each winding in a given series pair can either aid each other or cancel each other out. The net effect of improper winding orientation will be a gibberish motion and, in both cases, lots of heat.

    Parallel winding Bi-polar:
    With a parallel winding bi-polar configuration, two of the windings from each pair are connected in parallel. Again an "H-Bridge" driver pair us used to drive each parallel connected winding pair. And again, the connection orientating of each winding with reference to it's mate is critical. The net effects of improperly oriented winding pairs are no motion, gibberish motion and, in both cases, lots and lots of heat.

    With a series bi-polar configuration, the current is about half that of a parallel winding configuration. And typically, the series configured bi-polar configuration is connected to a higher operating voltage than the parallel configured bi-polar configuration.

    If memory serves, the series connected bi-polar configuration is capable of higher velocity, but lower torque that the parallel connected bi-polar configuration.

    So, three questions are in order here.

    1. Do you have a schematic diagram of the motor windings, showing what colors are associated with which winding and, what a winding make up a winding pair?

    2. Do you have the stepper drive configured for the configuration of your motor?

    3. Is the motor and drive configuration suitable for the selected input voltage?

    4. IS the PWM of the stepper driver appropriate for the class of stepper motor you are attempting to drive?


    Without a motor data-sheet and its associated wiring diagram, it is easy enough, determining which wires are connected to a given winding by doing an Ohms check with an Ohm Meter.

    However, determining the polarity of each winding and it's respective pair, without the corresponding motor data-sheet, the process becomes experimental, but it can be determined by connecting one winding pair at a time to the stepper motor drive and re-orienting the windings, until you get proper stepper motor rotor motion for each winding pair.

    From here it's only a matter of determining one winding pair orientation to the other winding pair.
     

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