Motor torque diminishes with increased microstepping.
Basically if your drives are set on full step resolution you will get your motors rated torque, however the torque diminishes via the following equation
T actual = Torque Rated x Sine of (90 / microstep setting)
Hence if you are running say 16microsteps.... you get about 9.8% of your motors rated torque...
Hi Rob,
Once, this info was correct but it is now many years out of date and still the myth continues to be perpetuated.
The manufacturer's of the various stepper driver chips (eg. Allegro/Toshiba/etc.) are well aware of the stepper motor characteristics and design their circuitry accordingly. Basically their chips are ‘smart’, using a form of back emf to proportionally increase the current through the energised windings to balance the available torque in relation to a micro-step position and shaft loading.
It’s a few years now since I carried out comparative angular deflection testing between a number of different manufacturer’s chips and I can confirm that the test stepper motor’s rotational shaft deflection, under a controlled load, (which is basically, holding torque) was within a knat’s whisker between whole step positions and micro-step positions.
Tweakie.
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