Re: [CAD_CAM_EDM_DRO] Re: Question on Power Supply - regulated notes

When you get down to basics all motors are pretty much the same. They
all rely on the rotor following a rotating magnetic field. The only
difference is in how the field is generated. Brush motors use a
mechanical commutator while the commutation is done electronically for
steppers and brushless servos.

If the motor is braking the absorbed energy has to go somewhere. Some
will be dissipated as heat and some will be turned into electricity and
sent back up the line (back EMF).

Les

Alan Marconett wrote:

>HI Dave,
>
>I wonder if there isn't a difference between a servo motor and a stepper in
>decelerating. Mariss has measured back EMF on the steppers, so we know it's
>there, but we still have to step the stepper motor. Probably a smaller
>current "drink" from the power supply. But as the windings still get
>energized, then I'd think we would still have drive power to cancel back
>EMF.
>
>Now on servos it's obvious that there is EMF. We actually drop the drive
>from a motor (small peristaltic pump) for a short bit of time in order to
>measure the back EMF, and use it to control the speed (servo loop).
>
>Good paper, by the way!
>
>Alan KM6VV
>
>
>