Electrical Knowledge by Sachin Sir

Q) If the back in a dc motor vanishes suddenly, the motor will A) Start hunting B) Burn C) Run at very high speed D) Run at very slow speed

Q) With the increase in speed of a dc motor A) Both back emf as well as line current increase B) Both back emf as well as line current fall C) Back emf increases but line current falls D) Back emf falls and line current increases

Q) Transformer ratings are given in _____________ a) kVA b) HP c) kVAR d) kW

Q) What is the working principle of a Transformer a) Transformer works on principle of self induction b) Transformer works on principle of mutual induction c) Transformer works on principle of amper law d) Transformer works on principle of coulomb law

Q) What is the function of a transformer? a) Transformer is used to step down or up the AC voltages and currents b) Transformer is used to step down or up the DC voltages and currents c) Transformer converts DC to AC v d) Transformer converts AC to DC v

Q) Use of fractional pitch winding A)Results in reduced leakage reactance B)Results in reduced axial length of the machine C)Makes it stiffer D)All of the above

Q) The frame of an induction motor is made of A) Aluminum B) Silicon steel C) Closed grained cast iron D) Stainless steel