Torque measurement system for valve actuators

A method for implementation by a valve actuator, the method comprising:

• actuating a valve using an alternating current (AC) motor of the valve actuator;
• measuring, by a microcontroller and during the actuating of the valve, a time interval between:
• (i) a first zero crossing of a waveform of AC voltage applied to the AC motor, and (ii) a second zero crossing of a waveform of AC current drawn by the AC motor;
• and
• determining, based on the time interval, an amount of torque produced by the AC motor during the actuating.

A method for implementation by a valve actuator, the method comprising:

• energizing an alternating current (AC) motor of the valve actuator from a power supply electrically coupled to the valve actuator;
• operating the AC motor to cause actuation of a valve coupled to the valve actuator;
• determining, by a microcontroller and during the actuation of the valve, a time of a first zero crossing of a waveform of AC voltage applied to the AC motor;
• determining, by the microcontroller and during the actuation of the valve, a time of a second zero crossing of a waveform of AC current drawn by the AC motor;
• measuring, by the microcontroller, a time interval from the time of the first zero crossing to the time of the second zero crossing;
• and
• determining, based on the time interval, an amount of torque produced by the AC motor during the actuation of the valve.