Textbook Problem

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How does the AC coil of the PFR receive the induced field current without receiving the full field current strength?

To determine

Explain the process of receiving induced field current by the AC coil of the PFR without receiving the full field current strength.

Explanation of Solution

The polarized field frequency relay (PFR) consists of two separate coils, one is the DC coil and other is the AC coil. When the rotor is not rotating, the rotating magnetic field produces induced current in the rotor circuit that supplies large current to the AC coil of the relay. When the rotor starts to rotate, the DC generator supplies the power to the DC coil of the PFR. The increasing speed of the rotor decreases the induced current in the rotor windings, and the frequency decreases in proportion to the speed of the rotor...