- Holding Torque / Max Static Torque
The maximum external torque that can be applied to an energized step motor at 0 pps without causing continuous rotation.
- Detent Torque
The torque required to rotate a non-energized step motor.
This torque results from the magnet of a hybrid or PM rotor motor.
- Step Accuracy
A measure of a step motor's maximum deviation from its desired or indicated position, calculated as a percentage of the step angle. This deviation is non-cumulative, meaning that the deviation found in any number of steps is no greater than the maximum deviation found in a single step.
- Torque / Speed Curve
Curve which shows the correlation between torque and speed.
A curve is for a given motor and a given driver.
- Pulse Rate
Rate that successive pulses are sent or steps are initiated.
- Start / Stop region
Area on or underneath the pull-in curve. For any load value in this region, the motor can start, stop, or reverse "instantly" (no ramping required) at the corresponding speed value.
- Max Starting Frequency
The frequency where it is possible to synchronize the step motor with its input frequency by accelerating and decelerating.
- Slew Range
The region between the pull-in and pull-out torque curves. A motor may operate in this range, but cannot start, stop or reverse without ramping.
- Max Running Speed
The maximum speed at which the motor can run without losing synchronism or missing steps from a standstill or stop without taking more steps than the pulses.
- Pull-in Torque (Curve)
The maximum torque, for a given speed, where a load can be accelerated into synchronism from a standstill.
- Pull-out Torque (Curve)
The maximum torque that can be applied to a motor operating at a given speed without losing synchronism.
- Resonance
When a motor operated on no load over the entire frequency range, one or more natural oscillating resonance points may be detected.
The range where a motors step rate is near the natural frequency of the motor is called resonance range. A motor operating in this range may experience excessive vibration.
Graph A