The sensor MRPM EX-AC is used exclusively for measuring the speed of brushless DC motors (BLDC). It is connected to any two motor phases and it calculates the current speed from the electrical course at the phases. With the help of the sensor MRPM-EX AC, current speeds and the past course of the propeller performance (minimum, maximum) can be monitored.

The sensor can be adjusted to set the timeout parameter which will be later announced to the user. Because the sensor is connected to the motor power system, the user must adjust the number of motor poles and the gear ratio of the transmission system to ensure proper operation. The information from the sensor are transmitted to the user via the Duplex system.