Need Help Determining Stepper Motor Voltage

Discussion in 'Electronics Resources' started by Best_Intentions, Jun 13, 2016.

  1. Best_Intentions

    Thread Starter New Member

    Jun 13, 2016
    3
    0
    Hi,

    This is my first post on All About Circuits so if I have posted this question in the wrong forum please feel free to correct me.

    My question is with regards to a stepper motor I have in my possession. It is made by Lin Engineering (or at least marketed by them) and has the following identifiers and specs. I am hoping that someone can supply the operating voltage of this motor. Lin Engineering does not list this specific motor. Any help would be appreciated.

    Motor Model: 5704X-03P-01

    NEMA 23 Body

    Wiring: Bipolar (4-Conductor)

    Amperage: 3.60

    Step Angle: 0.45 degrees

    75 oz. of holding torque.
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,553
    2,375
    Simple, supply a variable DC voltage to a winding and monitor the current, when it reaches 3.6Adc, record the voltage.
    Or measure the resistance of a winding.
    Max.
     
    KeepItSimpleStupid likes this.
  3. Best_Intentions

    Thread Starter New Member

    Jun 13, 2016
    3
    0
    Thanks much Max. I'll put it on a bench supply and use that method.
     
  4. Sensacell

    Well-Known Member

    Jun 19, 2012
    1,132
    267
    Note that the rated voltage and current are for DC operation. It would perform rather poorly at the rating listed on the nameplate.

    Most current regulated stepper drives use far higher voltages than the motor nameplate suggests...

    How do you intent to drive the motor?
     
  5. MaxHeadRoom

    Expert

    Jul 18, 2013
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    The bottom line when using it with a PWM controller for e.g. that operates with a higher DC voltage is that the name plate Current of the motor is not exceeded.
    Modern stepper controllers are designed to maintain this value over the rpm range.
    Max.
     
  6. Best_Intentions

    Thread Starter New Member

    Jun 13, 2016
    3
    0
    Thanks much for all replies. Since the nameplate shows 3.6 amps and one of the windings shows a resistance of 1.1 ohms I would have thought that a 36 volt power source would drive this motor. But after reading Sensacell's reply I think this motor would need higher voltages driving it to gain good performance.
     
  7. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,553
    2,375
    The bottom line is the name plate current should NOT be exceeded, the reason for the high PS voltage is that if the drive is designed simply for this current as the rpm increases so does the inductive reactance of the motor coil and current drops, therefore in order to provide the correct current as the rpm increases, a high voltage is applied accordingly to keep current constant.,
    The old method was simply to use a series resistor and a voltage calculated to provide the rated current, now modern drives use PWM as a more efficient method.
    Read any of the technical papers from any of the large stepper motor manuf. and they usually explain the reason for this torque loss with rpm, if no steps are taken.
    BTW, the static full torque voltage will be at 3.96vdc.
    Max.
     
  8. Marley

    Member

    Apr 4, 2016
    144
    40
    I agree. Modern stepper motor drivers use PWM to control the motor current from a much higher voltage. Often 48V or more. A high voltage allows a quick change in winding current and allows the motor to deliver more torque at higher speeds.

    Basically, each motor winding becomes part of a switchmode voltage dropper where the winding itself is the energy storage inductor. So even if the winding current is 3.60A (for example) the average current taken from the supply is much less.

    A resistor could be used but will be very wasteful of power.
     
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