Setting L297's chopper and L298's sense resistor for stepper motor

Discussion in 'The Projects Forum' started by crazybuoy, Apr 29, 2016.

  1. crazybuoy

    Thread Starter Active Member

    Sep 19, 2010
    62
    0
    I have a bipolar stepper motor with 3 ohm winding resistance, ~4kg weight and 160mm x 87mm dimension. I have not any other informations about this motor. I want to build driver using L297 & L298.

    I want to find following things according to above stepper motor:

    The value of sense resistors
    The value of variable-resistor in L297's chopper
    The recommended stepper power supply (L298 - pin 4)

    The schematic of L297's chopper attached. Is it suitable? You may recommend adding other component in this schematic.

    Edit: I have uploaded another schematic for limiting reference voltage for L297. Please suggest which one is more suitable.

    Please recommend above three things.

    Thanks in advance
     
    Last edited: Apr 29, 2016
  2. ScottWang

    Moderator

    Aug 23, 2012
    4,855
    767
    Please check the tag of stepper motor to see the values of V/I?
    Please attach your whole circuit, otherwise our members can't see the whole picture, so they can't give your the best suggestion.
     
  3. crazybuoy

    Thread Starter Active Member

    Sep 19, 2010
    62
    0
    Dear Sir,

    I have said already, that I have not any other informations about motor, because it has not any label or company name. I only checked winding resistance (3 ohm) with multi-meter.

    The driver circuit that I want to build is attached here. Again, I want to know these things:

    The value of both sense resistors
    The value of resistors in L297's chopper (L297-pin 15)
    The recommended stepper power supply (L298 - pin 4)
     
  4. ScottWang

    Moderator

    Aug 23, 2012
    4,855
    767
    The Vref is set for the peak current, the first circuit is set for all range as adjust from 0 to peak current, the second circuit is set for limits range, assuming that set for 1/2 peak current then the adjust range is 1/2(peak current) to the peak current, what is good that is depends on what you trying to adjust.

    You can also choose the voltage divider as 1/5(peak) to peak, 2/5(peak) to peak, 3/5(peak) to peak, 4/5(peak) to peak.
     
  5. crazybuoy

    Thread Starter Active Member

    Sep 19, 2010
    62
    0
    Thanks for very professional reply.

    Now I understand, that the first one with variable resistor and capacitor is better because it offers higher adjustable range.

    Please suggest the value of variable-resistor, because the range depends on this component. I have 100nf capacitor.
     
  6. ScottWang

    Moderator

    Aug 23, 2012
    4,855
    767
    Because the Vref was connected to the input of op amp inside of the L297, so I will suggest the value of variable-resistor is :
    R3 = Vcc/1 mA (in your first circuit, the R3 is a variable-resistor or called potential meter , normally we will use as VR1 or Pot1)

    exp: Vcc = 5V
    R3 = 5V/ 1 mA = 5K

    If you want to use 10 K then it should be ok, you can try different values and to feel the adjust feeling to match what you want.
     
    crazybuoy likes this.
Loading...