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Stepper motor driver

Discussion in 'Robotics & Mechatronics' started by Jabir, Mar 5, 2006.

  1. Jabir

    Jabir New Member

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    Hai evryone.

    I have a sanyo-denki 5.1v,1A,2kg-cm six wired stepper taken from an old
    dot matrix printer. Two wires are the center taps.
    I am using the unipolar configuration.

    We are using a "MINI 51" Evaluation Board Which consist of an Philips
    p89c668h micro controller of 8051 architecture for generating
    the signals for the stepper.

    Now The problem is The driving ckt. I made one with 2803.
    but the torque is low and the IC overheats quickly.
    The power supply indicated the current drawing is 700mA.

    Can i use TIP122 darlingtons for the job?
    Can i directly connect the TIP122 s with the microcontroller?
    I read somewhere that for increasing torque and speed we have to increase the supply voltage. Is it fine?
    Did it burns my motor?
    Also what is the procedure ? just increase the voltage?


    Plese help me.....
    (I am a mech engg student.So please describe more)


    Thanks in advance....
     
  2. waleed alhadidi

    waleed alhadidi New Member

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    Hi All
    i want to control a 3.8 V , 4 A bipolar stepper motor with saa1027 IC and i dont know how to amplify the output signal from the IC to the motor , can anyone help me ???? :?:
     
  3. bloody-orc

    bloody-orc New Member

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    use transistors or FET's. how you ask? ask google the same question. or at least try to find how to use transistors/mosfets in that kind of place.
     
  4. dave

    Dave New Member

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  5. ppppking04

    ppppking04 New Member

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    L297-298

    Hello,
    I would suggest you use L297 and 298 Ic's for driving the stepper motor...google it for its datasheets...i ve found them useful for driving steppers...
     
  6. bloody-orc

    bloody-orc New Member

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    or use 2 A3955 chips. those little bastards are perfect for the job. they even have microsteping. and also PWM. datasheet can be found in here: www.alldatasheets.com
     
  7. philba

    philba New Member

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    another choice is the L293 plus a little logic (inverter). the L293D has built-in diodes and can handle the current. use the L293 as 4 half H-bridges to drive each phase of the stepper. Use them as low side drivers. The L293D is like $2 from mouser.

    what voltage are you using to drive the stepper? Does it have a resistance or voltage on the lable? the reason I ask is because if you run too high a voltage through it, the current will be too high and you could over-heat it.

    If that's the case, you can PWM it and reduce the current while keeping voltage (and torque) up. worse case, you can use power resistors to control the current.

    on the 4A stepper that was asked about - you need a pretty heavy duty controller. that is beyond the scope of this discussion. I'd look at getting a Gecko driver or similar. not cheap.

    Phil
     
  8. Jabir

    Jabir New Member

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    Hello all.

    Thanks for the discusion.

    Sorry,i am a mechanical engg. student .So i dont prefer ICs. :oops: since i am not familiar with electronics.

    I am using the unipolar config which deliver enough torque for my robo..
    I made driver ckt using TIP122 darligtons. It works fine in 6 V,10 AH battery below 60 rpm.
    But when trid to increase speed the motor starts vibration

    Did you know the sln?
    I am ready to increase voltage. Please tell me the procedure...

    Thanks in advance
    Jabir
     
  9. philba

    philba New Member

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    I would first try to figure out the other problems before increasing the voltage. are you certain you have the step sequence correct?

    How big is your stepper? printer steppers tend to be pretty small, maybe it's just too small for the load you are placing on it.

    Maybe you are already over-voltage? does the motor get hot? Have you measured the ohms of the coils? This should tell you the current draw. Measure the half coils and then use that to calculate current draw. For example, I have a stepper I pulled out of an inkjet printer. each half coil measures pretty close to 20 ohms (it's also printed on the label). at 12V, this would pull 600 mA per coil. No voltage is on the label but I'm pretty sure it couldn't handle 600 mA - the wires are pretty small probably 32 ga or smaller. I'd try reducing the voltage to see what happens.

    If step sequence and voltage are right, it sounds like mis-aligned shafts or resonance. Resonance at 200 steps/sec is kind of unlikely (60 rpm - 1 r/sec, 1.8 deg/step is 200 steps). my guess is misalingment. how does it perform with motor shaft not connected?
     
  10. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    That sounds about right, 60rpm is about as fast as a stepper motor will run off it's rated supply. To increase speed you need to feed it from a higher voltage with current limiting resistors - if you google for "stepper motor tutorial" you will find all you need to know.
     
  11. Jabir

    Jabir New Member

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    Thanks

    My stepper is a Sanyo-denki, 550 gram weight, 52 mm in dia, 57 mm length ,5.1 volt, 1 amp 200 step/rev and six wired motor....
    My step sequence is right. I found it using trial and error method..The rotation is perfect under no load and there is no chances of resonance. I am testing it with no load.

    I had already measured the current drawn from the battery, 1.16 A just above the rated .
    I had read many tutorials.. But unfortunately i cant understand the logic of adding current limitting resistors. sorry.. :cry:

    help me if you have time....
    Regards

    Jabir
     
  12. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Re: Thanks

    Try http://www.electro-tech-online.com/custompdfs/2006/03/00907a.pdf, page 13 onwards.
     
  13. Mike - K8LH

    Mike - K8LH Well-Known Member

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    Jabir,

    The current limiting resistors provide additional initial voltage to the stepper motor coils until the current catches up enough to develop the proper voltage drop across the resistor...

    My 5v/1a NEMA-23 steppers didn't have much power/torque when I ran them from 5 volts... Running them from 12 volts with current limiting resistors made a big difference...

    Please note that you can also "torque step" the steppers by energizing two coils for each step... This then requires 2-amps current each step but the power/torque improvement is quite significant...

    Good luck with your project... Kind regards, Mike

    [​IMG]

    [​IMG]
     
  14. bananasiong

    bananasiong New Member

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    here is the circuit that i just tried! it works with very high torque. i can drive the stepper in 12V with 5V signal.

    any npn can be used in this circuit, as long as they can drive up to 800mA.

    make sure that this circuit and the microcontroller have the common ground, i mean the -ve port of microcontroller should be connected to the -ve terminal of the supply.


    if u want to drive the stepper motor higher than 5V, don't connect the D5, D6, D7 and D8 to the +ve port of the microcontroller, connect them to the Vcc.


    it really works!!
     

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  15. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    I recognise that diagram! :lol:

    It's really THAT simple to drive a stepper motor.
     
  16. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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  17. Jabir

    Jabir New Member

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    Hai all

    i solved the problem.....

    Tanks for sugessions and help and special cheers to Mike, K8LH :lol:
    ur logic works .

    Regards to all..................................bye
    Jabir
     
  18. lavanyarammohan

    lavanyarammohan New Member

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    stepper motor coil identification

    hi am using a stepper motor taken from a floppy drive.. it has 4 wires colored blue,white,red and yellow. am unable to find the cils properly. can any one suggest how to.. which wire cats as a,a-.. am using L293D drive ic to drive the motor. so can anyone help me in finding out the coil values..
     
  19. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    I suggest you google for 'stepper motor tutorial', there's plenty of help out there.

    As your motor only has four wires it's going to be a bipolar motor, so you should have two completely seperate windings, easily indentified with a meter.

    Once you've found the two windings, use a battery and a couple of pieces of wire to find the step sequence you need.

    For a start, label the wires, 1-2 for one winding, and 3-4 for the other. Apply the battery, positive to 1 and negative to 2, and see which way it moves, then apply positive to 3 and negative to 4, and see if it moves the same way - you now know the polarity of the coils.
     
  20. Jabir

    Jabir New Member

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    hey lavanya ram mohan..

    i lke that name !!!!!!! :D :D :D

    use this figure for lead identification...

    JABIR
     

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  21. bibinjohn

    bibinjohn New Member

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