Re: Torque when using Micro Step or Full Step

Hans,

The answer is somewhat involved so bear with me.

Step motor mfgs list a holding torque for their motors. They do that
because it is a universal specification that can be tested by anyone
by applying a torque wrench to the motor.

Holding torque by itself has little application in the real world
except as a measure of comparison to other motors. A little-listed
specification is dynamic torque. This is the torque a motor has when
it is being driven by a full-step drive at 5 full-steps per second.

Dynamic torque is usually 35 to 40% less then the holding torque.
Where did the missing 35 to 40% go? It went to resonate the motor.

A microstep drive starts off with a disadvantage regarding holding
torque. It develops only 70.7% of the holding torque a full-step
drive does.

That is not where the action is though. It's "dynamic torque" loss is
in the region of 3 to 4%. That is because compared to a full step
drive, it invests less than 1% of its energy into resonance. Once the
motor begins to move, tha microstep drive has the advantage an it
keeps that advantage over the full speed range as well.

Regarding your motor. Check carefully to see if it has not been
disassembled. Look for marks on its screws. A step motor that has had
its rotor removed from the stator can lose a lot of its rated torque
due to demagnetization.

Mariss

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Hans Wedemeyer <xyz@h...>
wrote:

> I'm still mulling over the lack of startup power this PACSI motor

has , and was wondering if there

> is much difference in torque output Micro Step and Full Step.
>
> The Gecko 201 only does micro-step.
> Would there be any increase in torque using Full Step as compared

to Micro Step ?

>
> Best Regards
> Hans W