Re: [CAD_CAM_EDM_DRO] How do you compare steppers to servos

As you say virtually all motors rely on magnetic fields. My point is
that steppers are not rigid. They are springy due to these magnetic fields.

Servos are naturally even more springy but the electronics compensate
for this. Steppers being open loop have no compensation. Try it
yourself. Attach a bar to the shaft of a stepper and apply a force to
that bar. It will move. As long as you stay within +/- 2 steps it will
return to the correct position as soon as you remove the force. If you
exceed the motor's holding torque the motor will then jump position and
you have lost steps.

If you repeat the above experiment with a servo it will also give a
small amount until the electronics compensate and fight back. If you
exceed the system's maximum torque the drive will still keep fighting up
until you fault the drive due to over current or excessive following error.

Les


My point is that contra

On 26/02/11 01:52, Jeffrey T. Birt wrote:
>> A stepper works by making the rotor follow a
>> magnetic field generated by the coils.
>
>
> As does any electrical motor. I'm not I follow the point your trying to
> make.
>
>