Re: Question on Power Supply - regulated notes

Hey guys!
This is an interesting and informative thread. Please don't stop!
It may have been repeated, or way beyond the technical knowhow of
some of us, or so utterly simple it should have already been known,
OR It may have not even occurred to us that it was even remotely
important. So you guys please keep asking questions and you other
guys keep answering them or steering them in the right direction,
and the rest of us will absorb as much as we can like a dried out
old sponge.

Randy

Oh yeah, and have a fantastic time at the meeting get together.





--- In CAD_CAM_EDM_DRO@yahoogroups.com, Les Newell <lesnewell@h...>
wrote:

> 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
> >
> >
> >