DGVCL Exam Paper (12-06-2016) Which of the following is the least expensive protection for over current in low voltage system? Rewireable fuse Oil Circuit breaker Isolator Air break circuit breaker Rewireable fuse Oil Circuit breaker Isolator Air break circuit breaker ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (12-06-2016) A relay used for protection of motors against overload is : Thermal relay Electromagnetic attraction type Buchholz's relay Impedance relay Thermal relay Electromagnetic attraction type Buchholz's relay Impedance relay ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (12-06-2016) What will happen if the primary of a transformer is connected to DC supply? Transformer will operate with low efficiency Transformer will operate with high efficiency No effect Transformer may start to smoke and burn Transformer will operate with low efficiency Transformer will operate with high efficiency No effect Transformer may start to smoke and burn ANSWER EXPLANATION DOWNLOAD EXAMIANS APP transformer works on principle of faraday's law of electromagnetic induction. So if D.C supply use, no indction are produced and due to this E.M.F not induced in winding and transfer of electrical energy is not possible.
DGVCL Exam Paper (12-06-2016) Which of the following circuit breakers has high reliability & minimum maintenance? Vacuum CB Bulk oil type CB Air blast CB Sulphur hexafluoride CB Vacuum CB Bulk oil type CB Air blast CB Sulphur hexafluoride CB ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (12-06-2016) Core type transformers are popular in _____ High voltage applications Low voltage applications None of these All of these High voltage applications Low voltage applications None of these All of these ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (12-06-2016) What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to a 500 Hz (frequency) source of the same voltage: Transformer may start to smoke and burn Eddy Current and Hysteresis losses will be excessive Current will be too much high No effect Transformer may start to smoke and burn Eddy Current and Hysteresis losses will be excessive Current will be too much high No effect ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Core loss of transformer = Hysteresis loss + eddy current lossHysteresis loss prpotional to feddy current loss prpotional to f².
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