LADWP Electric Station Operator – Circuit Breakers, Disconnects, Transformers Practice Test

Back emf is the voltage generated in a motor winding due to electromagnetic induction as the conductors move through the magnetic field. This induced voltage opposes the applied supply voltage, following Lenz’s law, and its magnitude grows with speed. Because it arises from the changing magnetic flux in the same winding, it is classified as an induced voltage. The terms self or mutual relate to coil-to-coil coupling, which isn’t what back emf refers to here, and while emf is a general elektromotive force, the specific nature of back emf is that it is induced.