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Stepper motor voltage? — Parallax Forums

Stepper motor voltage?

ArchiverArchiver Posts: 46,084
edited 2000-08-16 16:26 in General Discussion
Hello everyone,
I'm using a stamp to drive a stepper with a SN754410NE
(L293D clone). I've got the stepping sequence and code working with a 9
volt stepper that's 37 ohms/winding. This motor has only 25 steps per
revolution. I would like to use another small stepper I have, the same NEMA
size, that has 200 steps per revolution. I do not know the operating
voltage of this motor but the resistance per winding is awfully low at 1.33
ohms. What voltage is typical for this rating? I would really like to get
this working, but suspect that it's going to draw too much current for my
driver chip. Any ideas?

Duncan

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2000-08-15 22:44
    Duncan:
    I have seen ads for steppers as low as 3.3 volts. As a start, I would
    assume your stepper is made for 3-5 volts. At 3.3 volts, it would draw 2.3
    amps; and 3.8 amps at 5 volts. The IRL530N logic-level mosfet from Digikey
    is great for this. It can handle up to ~15 amps, and has on resistance of
    0.11 ohms driven from a stamp. I drove a 5 volt, 1.44 amp stepper, (3.5 ohm
    coils), from these devices with hardly any temp rise on the IRLs when driven
    from a PIC. It is a good idea to use a series resistor between the Stamp
    pin and the mosfet gate to prevent oscillations of the FET as well as giving
    some protection to the Stamp. You can use 1-5 kohms. If your stepper is
    bipolar you need a bootstrapped full bridge with the N-channel devices, or
    use two N-channels and two P channels, (IRF9Z34 may work, but they are not
    logic level devices).

    Ray McArthur

    Original Message
    From: <orthner@s...>
    To: <basicstamps@egroups.com>
    Sent: Tuesday, August 15, 2000 5:11 PM
    Subject: [noparse][[/noparse]basicstamps] Stepper motor voltage?


    >
    > Hello everyone,
    > I'm using a stamp to drive a stepper with a SN754410NE
    > (L293D clone). I've got the stepping sequence and code working with a 9
    > volt stepper that's 37 ohms/winding. This motor has only 25 steps per
    > revolution. I would like to use another small stepper I have, the same
    NEMA
    > size, that has 200 steps per revolution. I do not know the operating
    > voltage of this motor but the resistance per winding is awfully low at
    1.33
    > ohms. What voltage is typical for this rating? I would really like to get
    > this working, but suspect that it's going to draw too much current for my
    > driver chip. Any ideas?
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-15 23:39
    I have done a lot with steppers, stamps and pics. I have found that the
    motor's rated voltage is to obtain the rated current. If you raise the
    voltage, the current will increase. If you lower the voltage, you will also
    lower the current, however youmight not have enough torque to make the motor
    turn under load. You can start out at a low voltage and increase it until
    the motor runs. You might have to resort to a heavier driver chip to handle
    the current. I have often run 12 volt steppers at 24 and even 48 volts to
    generate enough torque to make the motor move under load. This will cause
    the motor to draw considerably more currnet. You might want to use a UDN2998
    chip as the driver. Cost is less than $7 and manufacturer is Allegro. You
    can look at the data sheet at www.allegro.com The chip is good for several
    amps continuous and even more if run intermittently. You will have to change
    the truth table for stepping as the chip has enable A, phase A, enable B and
    phase B inputs. It will drive either unipolar (6 or 8 wires) or bipolar (4
    wires) motors. I have a BS2 program that will run this chip and enable you
    to talk to the controller via the serial port on your pc. I also have a
    program written for the 16F84 PIC microcontroller (about $6) that works with
    the Allegro chip as well. If interested, I will be glad to email you either
    or both programs.

    Best regards,
    Gary

    G. Shearer
    Free Electron Laser Research Center
    Vanderbilt University
    Nashville, Tennessee
    Original Message
    From: orthner@s... <orthner@s...>
    To: basicstamps@egroups.com <basicstamps@egroups.com>
    Date: Tuesday, August 15, 2000 4:12 PM
    Subject: [noparse][[/noparse]basicstamps] Stepper motor voltage?


    >
    > Hello everyone,
    > I'm using a stamp to drive a stepper with a SN754410NE
    >(L293D clone). I've got the stepping sequence and code working with a 9
    >volt stepper that's 37 ohms/winding. This motor has only 25 steps per
    >revolution. I would like to use another small stepper I have, the same NEMA
    >size, that has 200 steps per revolution. I do not know the operating
    >voltage of this motor but the resistance per winding is awfully low at 1.33
    >ohms. What voltage is typical for this rating? I would really like to get
    >this working, but suspect that it's going to draw too much current for my
    >driver chip. Any ideas?
    >
    >Duncan
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-16 01:52
    Hi, I am new to the world of steppers and would like to drive them with my
    BS2 or another PIC. can you send me your programs and possibly some
    explanations with them and schematics. Did you see my post from earlier
    today with the subject of ...Speaking of stepper motors...? Thanks

    -Dan


    Original Message
    From: "G. Shearer" <g.shearer@v...>
    To: <basicstamps@egroups.com>
    Sent: Tuesday, August 15, 2000 3:39 PM
    Subject: Re: [noparse][[/noparse]basicstamps] Stepper motor voltage?


    > I have done a lot with steppers, stamps and pics. I have found that the
    > motor's rated voltage is to obtain the rated current. If you raise the
    > voltage, the current will increase. If you lower the voltage, you will
    also
    > lower the current, however youmight not have enough torque to make the
    motor
    > turn under load. You can start out at a low voltage and increase it until
    > the motor runs. You might have to resort to a heavier driver chip to
    handle
    > the current. I have often run 12 volt steppers at 24 and even 48 volts to
    > generate enough torque to make the motor move under load. This will cause
    > the motor to draw considerably more currnet. You might want to use a
    UDN2998
    > chip as the driver. Cost is less than $7 and manufacturer is Allegro. You
    > can look at the data sheet at www.allegro.com The chip is good for several
    > amps continuous and even more if run intermittently. You will have to
    change
    > the truth table for stepping as the chip has enable A, phase A, enable B
    and
    > phase B inputs. It will drive either unipolar (6 or 8 wires) or bipolar (4
    > wires) motors. I have a BS2 program that will run this chip and enable you
    > to talk to the controller via the serial port on your pc. I also have a
    > program written for the 16F84 PIC microcontroller (about $6) that works
    with
    > the Allegro chip as well. If interested, I will be glad to email you
    either
    > or both programs.
    >
    > Best regards,
    > Gary
    >
    > G. Shearer
    > Free Electron Laser Research Center
    > Vanderbilt University
    > Nashville, Tennessee
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-16 02:47
    At 05:39 PM 8/15/00 -0500, Gary wrote: that he would contribute a program
    to run steppers with a 16f84 and Allegro chip. I would sure like to have a
    copy of your program Gary. I have a zillion hard drive motors and would
    like to drive a few.
    My e-mail is w5tnj@c... thanks ==MAC==
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-16 04:14
    Use more than one driver... I'm using two per (gearhead) motor, seems to work
    fine! (or at least until i accidentally stall the motor)


    Hope this helps,
    Edward Kindler
  • ArchiverArchiver Posts: 46,084
    edited 2000-08-16 16:26
    OK Dan,
    I would be glad to send along a paper I wrote using the PIC. It has diagrams
    of the discussion and the final circuit. It would be very easy to modify the
    circuit for a stamp. You will see. If you want the stamp program, I will
    look at work for it and send it along too.

    Best of luck,
    Gary

    Original Message
    From: "Gliebe-Tronics" <gliebetronics@h...>
    To: <basicstamps@egroups.com>
    Sent: Tuesday, August 15, 2000 7:52 PM
    Subject: Re: [noparse][[/noparse]basicstamps] Stepper motor voltage?


    > Hi, I am new to the world of steppers and would like to drive them with my
    > BS2 or another PIC. can you send me your programs and possibly some
    > explanations with them and schematics. Did you see my post from earlier
    > today with the subject of ...Speaking of stepper motors...? Thanks
    >
    > -Dan
    >
    >
    >
    Original Message
    > From: "G. Shearer" <g.shearer@v...>
    > To: <basicstamps@egroups.com>
    > Sent: Tuesday, August 15, 2000 3:39 PM
    > Subject: Re: [noparse][[/noparse]basicstamps] Stepper motor voltage?
    >
    >
    > > I have done a lot with steppers, stamps and pics. I have found that the
    > > motor's rated voltage is to obtain the rated current. If you raise the
    > > voltage, the current will increase. If you lower the voltage, you will
    > also
    > > lower the current, however youmight not have enough torque to make the
    > motor
    > > turn under load. You can start out at a low voltage and increase it
    until
    > > the motor runs. You might have to resort to a heavier driver chip to
    > handle
    > > the current. I have often run 12 volt steppers at 24 and even 48 volts
    to
    > > generate enough torque to make the motor move under load. This will
    cause
    > > the motor to draw considerably more currnet. You might want to use a
    > UDN2998
    > > chip as the driver. Cost is less than $7 and manufacturer is Allegro.
    You
    > > can look at the data sheet at www.allegro.com The chip is good for
    several
    > > amps continuous and even more if run intermittently. You will have to
    > change
    > > the truth table for stepping as the chip has enable A, phase A, enable B
    > and
    > > phase B inputs. It will drive either unipolar (6 or 8 wires) or bipolar
    (4
    > > wires) motors. I have a BS2 program that will run this chip and enable
    you
    > > to talk to the controller via the serial port on your pc. I also have a
    > > program written for the 16F84 PIC microcontroller (about $6) that works
    > with
    > > the Allegro chip as well. If interested, I will be glad to email you
    > either
    > > or both programs.
    > >
    > > Best regards,
    > > Gary
    > >
    > > G. Shearer
    > > Free Electron Laser Research Center
    > > Vanderbilt University
    > > Nashville, Tennessee
    >
    >
    >
    >
    >
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