Balanced Earth Fault Protection: In small-size alternators, the neutral ends of the three-phase windings are often connected internally to a single terminal. Therefore, it is not possible to use Merz-Price…
Differential Protection of Alternators: The most common system used for the protection of stator winding faults employs circulating-current principle (Refer back to Art. 21.18). In this scheme of Differential Protection…
Relay Timing Circuit: An important characteristic of a relay is its time of operation. By the Relay Timing Circuit of operation is meant length of the time from the instant…
Protective Relay: A Protective Relay is a device that detects the fault and initiates the operation of the circuit breaker to isolate the defective element from the rest of the…
Sequence Impedance of Power System: Each element of power system will offer impedance to different phase sequence components of current which may not be the same. For example, the impedance…
Induction Regulators: An induction regulators is essentially a constant voltage transformer, one winding of which can be moved w.r.t. the other, thereby obtaining a variable secondary voltage. The primary winding is…
Machine Tools Motors Requirements: The Machine Tools Motors Requirements are: The motors must be reliable and low cost, requiring less maintenance. They must be capable of speed control. Some applications…
Torque Equation of DC Motor: When dc voltage is applied to the armature of a dc motor with its field excited by dc, a torque is developed and the armature…