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Stepper or DC motor — Parallax Forums

Stepper or DC motor

ArchiverArchiver Posts: 46,084
edited 2003-10-20 22:22 in General Discussion
Can I control the speed of a DC motor. Can someone explain me the
diference between a stepper and a dc motor.

The program from parallex about the stepper motor: is the motor
continue running, or with intervals?

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-10-20 22:22
    --- In basicstamps@yahoogroups.com, "Juliano" <drieelot@y...> wrote:
    > Can I control the speed of a DC motor. Can someone explain me the
    > diference between a stepper and a dc motor.
    >
    > The program from parallex about the stepper motor: is the motor
    > continue running, or with intervals?


    The simple difference is that a DC motor will contine to spin when
    power is applied.

    the stepper acts like a bunch of electro magnets. when power is
    applied, the armiture is pulled to one point and locks up and just
    stays there.

    you need to de-energize that coil and energize another to get it to
    move to the next point. in otherwards, it acts like a brake more
    than a motor it that way.

    by energizing one coil the armiture will move to that poistion, then
    by keeping that one energized and energizing the other, it will go
    halfway between.

    deeneegize the first and it will move to the second point. repeat
    often and the motor will walk around.

    by determining the power needed for each coil, you can (this is
    concept stuff, not engineering stufff) apply 1/4 power to one coil
    and 3/4 to another to get the motor to move 1/4 between the 2 full
    steps.


    so coil A ON
    coil B on 1/4 Coil A on 3/4
    both at 1/2
    B at 3/4 A 1.4
    then A off, B ON
    would offer 4 steps between the natural steps of the motor.

    There is a microstepping method that does that for 4,8,10,16, 23.....
    steps BETWEEM the natural steps. but, it requires one pulse to move
    on step, or one pulse to move one microstep. or in otherwards,
    mircrostepping reduces the maximum step rate by using the pulses to
    do fractional movements.

    Hope that helps a little.

    Dave
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