Re: [CAD_CAM_EDM_DRO] motor types

Howdy John~!

So you mean to tell me that a "servo" is
just a "brushless dc" motor with an encoder attached? (:o)

So, if my Pop tells me he has a "brushless dc" motor with
a little round black box attached to the back of it
that has wires coming out of it, I should run, not walk, to go get it?

I can't believe it's that simple...Brushless DC + Encoder = Servo.

Thanks, John.

Weyland


From: <info.host@...>

>
> Every motor in your machines will be brushed. Brushless motors are
> backwards, they have the magnets on the inside and the coil around the
> outside, brushed is magnets outside coils inside (A normal motor). The

major

> difference is that the brushed motors have brushes connecting the current
> supply to the coils as they turn so the rotor has a drag 'needlessly' put

on

> it. There are different ways of transferring the energy to the coils but
> brushes is the cheapest. Brushless motors have a stationary coil so there

is

> no drag put on the rotor except by the imperfect bearings. Brushless

motors

> are used when the job is critical or needs doing accurately. Brushless are
> much more expensive. Model electric planes (Electric powder prop!) use
> brushless motors in place of brushed and that makes the motor worth
> something above £100. A servo is a motor that gives feedback of it's
> position. In CNC encoders give the feedback to the controller to tell it
> where it's made a mistake ect. In model planes the same thing happens but
> the feedback is fed straight into the servo's own mini correction system.
> For CNC you will use brushless motors. You stick you're encoder on the

motor

> and hey.... you have a servo. Plug the encoder into your controller and

you

> have a close loop system, that is the system can report back on itself.

You

> can miss out on the encoders and have an open loop system, like most

stepper

> systems.
>
> John