Recent questions tagged relays

Description : IDMT relays are used to protect the transformer against :  (A) Internal short -circuits (B) Open circuits (C) External short circuits (D) Oil leakage

Last Answer : IDMT relays are used to protect the transformer against : External short circuits

Description : Consider the following statements. Which of these statements are correct ?  (1) Reactance relays are preferred for ground fault relaying  (2) Impedance relays are most suitable for:protecting long transmission lines  (3) Mho relays are best ... (1) and (3) (C) (2) and (4) (D) (1), (2) and (4)

Last Answer : Consider the following statements. Which of these statements are correct ?  (1) Reactance relays are preferred for ground fault relaying  (2) Impedance relays are most suitable for:protecting long transmission lines  (3) Mho relays are ... (1) and (3) (C) (2) and (4) (D) (1), (2) and (4)

Last Answer : The inverse definite mean time relays are used for over current and earth fault protection of transformer against internal short-circuits.

Last Answer : The single phasing relays are used for the protection of three phase motors.

Last Answer : Impedance relays are used for phase faults on long line.

Last Answer : Discrimination between main and back up protection is provided by the use of relays which are slow.

Last Answer : To protect most of the electrical equipment handling low power, the types of relays used are thermocouple, electronic and bimetallic.

Last Answer : Protective relays are devices that detect abnormal conditions in electrical circuits by measuring constantly the electrical quantities which differ during normal and abnormal conditions.

Last Answer : Directional relays are based on flow of power.

Description : D.C. shunt relays are made of?

Last Answer : D.C. shunt relays are made of many turns of thin wire.

Last Answer : Thermal overload relays are used to protect the motor against overcurrent due to heavy loads.

Last Answer : Overload relays are of induction, solid state, thermal, electromagnetic type.

Last Answer : Relays can be designed to respond to changes in resistance, reactance or impedance voltage and current, light intensity, temperature.