What is the relevance of back emf of a motor and the function of a motor in relation to Lenz’s Law and the law of conservation of energy?

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What is the relevance of back emf of a motor and the function of a motor in relation to Lenz’s Law and the law of conservation of energy?

In: Physics
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Back EMF is more or less the impedance of the motor under load. At standstill, there is only the resistance of the wire. When an AC field in the armature creates an alternating magnetic field that cuts across the elements of the rotor, it induces circulating current in the rotor that opposes the field that created it (Lenz Law). Torque is produced and the motor starts spinning, which generates a Counter EMF that is proportional to the rpms. This is why you see an inrush of current at start up that decays to a fraction once the motor is at full speed. At that point, CEMF is maximum and, since it is generated in opposition to the field that created it, minimizes the current draw to charging currents and friction loss.