Thermal Relay | Thermal Relay Objective Type Questions and answers

36.  A bimetal strip, in a thermal relay, consist of two metal strips of different

   A. Specific heat

   B. Thermal conductivity

   C. Coefficients of expansion

   D. All of the above

37.  Thermal relays are used for protection of motors against over current owing to

   A. Short circuits

   B. Heavy loads

   C. Earth fault

   D. All of the above

38.  Thermal relay are often employed in

   A. Motor starters

   B. Transformer protection

   C. Generator protection

   D. None of the above

39.  Two input phase comparator in a static relay is made up of a

   A. transformer amplifier

   B. Transistor logic circuit

   C. Rectifier Bridge

   D. Thyristor Bridge

40.  The phase comparators in case of static relays and electromechanical relays normally are

   A.. Cosine and sine comparators respectively

   B. Sine and cosine comparators respectively

   C. Both are sine comparators

   D. Both are cosine comparators

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