The rotor position is determined using the progression of the induced voltage. The electronics evaluate the zero crossing of the induced voltage (EMF) and commutate the
motor current after a speed dependent pause. However, for lower speeds and more precise controls amplifiers with hall sensor evaluation are preferable.
The speed controller in the quadrant EC amplifier sensorless EC motors compares the present commutation frequency with the set value and adjusts the speed
if there is a difference.
The actual rotor position is evaluated by using the Back-EMF sensing technique. Different start sequences with varying startup procedures can be easy selected.
Speed can be monitored through the speed monitor output. Different protective functions safeguard the motor and amplifier.