Introduction to Motor Data

The first and most important step in selecting your SmartMotor™ is determining the load characteristics. Below is a review of understanding torque curves and understanding power curves. Motor sizing parameters are primarily based on torque curve and moment of inertia, and with these two factors users can find the ideal operating bandwidth and use it to ensure proper SmartMotor™ servo size choice.

Torque Curves

Understanding Animatics Torque Curves

Each set of torque curves depicts limits of both continuous and peak torque for the given SmartMotor™ over their full range speed.

Peak Torque Curve:

The Peak Torque Curve is derived from dyno testing and is the point at which peak current limit hardware settings of the drive prevent further torque in an effort to protect drive stage components.

Continuous Torque Curve:

The continuous torque curve is also derived from dyno testing, but is instead the point at which the temperature rises from an ambient of 25ºC to the designed thermal limit.

For example, the motor will be placed on the dyno tester and set to operate at 1000 RPM continuously with the load slowly increased until the controller reaches its maximum sustained thermal limit. This limit is either 70ºC or 85ºC depending on the model number. All PLS2 SmartMotors are set to 85ºC.

The far lower right side of the curve is limited by supply voltage. This is the point at which Back EMF suppresses any further speed increase. Higher supply voltages will shift the zero torque point of the curves further to the right.

Ambient Temperature Effects on Torque Curves and Motor Response:

If the motor is operated in an environment greater than 25ºC, then it will reach its thermal limit faster for the same given load thereby further limiting continuous torque.

Therefore; any given motor torque curve MUST BE linearly de-rated for a given ambient temperature from 25ºC to 70ºC, 85ºC for all PLS2 SmartMotors.

Supply Voltage Effects on Torque Curves and Motor Response:

Higher voltages have two-fold effects on torque curves. As mentioned above, raising voltage will shift the curve to the right. It will also allow higher current into the drive. However, torque curves depict torque at a given velocity.

If you double supply voltage, the motor can sustain twice the original velocity. But since acceleration is the differential of velocity, it can achieve 4 times the original acceleration. This is useful for high speed indexing and fast start/stop motion.

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