Re: [CAD_CAM_EDM_DRO] Brushless DC motor.....

RC wrote:

> Does anyone know if the Vexta Brushless DC motor, sample model #BLD1524-F, is the same as a dc servo motor? Any information about how they would work in a cnc application also.

It is really not a DC motor. It is essentially a permanent magnet AC motor. The only
true DC motor uses brushes. (yes, some purists may flame me over this.) The term
"Brushless DC" motor was coined when those motors were used in fans, because
they are treated as if the were brush motors, except there are no brushes to wear out.
When you want to reverse it, or extract energy when braking, then it gets a LOT
more complex, and 2 wires won't do it any more. So, these motors have 3 power
wires, generally, and more for the encoder that at least tells the drive which windings
need current in which direction.

Generally, you need a brushless servo motor drive to use these motors. because
the arrangement and phasing of the encoders are not completely standard on these
motors, it is pretty risky to try using motors from one manufacturer with drives from
someone else. So, for most applications, consider the motor and drive as a package.

They work fine for CNC, have longer, trouble-free life than a PM brush DC motor,
although that is not likely to be a concern for hobby and small-shop class machines.

Jon