Re: [CAD_CAM_EDM_DRO] servo motor

Dave Fisher wrote:

>>From my use of many types of DC motor - Regular DC motors
>will perform just as well as motors speced as 'Servo Motors'
>
>Mechanical construction of Servo Motors is often better and
>they often use more than 2 brushes to get more current to the
>armature. LOTS of good surplus DC motors from main frame tape drives or
>avaialable on the net - these perform very well
>
>

Not exactly. The motors with 4 brushes are 4-pole motors. Not so
different from 2-pole and 4-pole motors in AC service. The 4-pole
motors often are optimized for more torque at lower speeds than
2-pole. If the motor has 4 brushes, you will find internally, there
will be 4 magnet poles for the field, too. A 2-brush motor will only
have 2 field poles.

Jon