12.What is slip in an induction motor?
Slip can be defined as the difference between the flux speed (Ns) and the rotor speed (N). Speed of the rotor of an induction motor is always less than its synchronous speed. It is usually expressed as a percentage of synchronous speed (Ns) and represented by the symbol ‘S’.
13. Why rating of transformer in KVA and for motor rating isi n hp or KW.
Transformer losses depends on current (CU loss) & Voltage (Iron loss) (VA). So its rated in KVA. Also TFR is independent from load PF. But in motor the losses depends of load power factor. That's why motor rated in KW.
14. For a transmission line, if the magnitude of open circuit input impedance is 100 Ω and magnitude of short circuit input impedance is 25 Ω then the characteristic impedance of transmission line will be .........
15. How is the feed water coming to the economizer in a thermal power plant is heated?
16. Why use the VCB at High Transmission System ? Why can't use ACB?
Actually the thing is vacuum has high arc queching property compare to air because in VCB ,the die electric strengths equal to 8 times of air . That y always vaccum used as in HT breaker and air used as in LT .
17. In the output of..............type of power amplifier crossover distortion is exhibited.
18. Why link is provided in neutral of an ac circuit and fuse in phase of ac circuit?
Link is provided at a Neutral common point in the circuit from which various connection are taken for the individual control circuit and so it is given in a link form to withstand high Amps. But in the case of Fuse in the Phase of AC circuit it is designed such that the fuse rating is calculated for the particular circuit (i.e load) only.So if any malfunction happen the fuse connected in the particular control circuit alone will blow off.
19. Total 8 memory chips are present in a memory system. Each memory chips has 12 address lines and 4 data lines. The total size of the memory system is.........
32 K bytes
20. Why back emf used for a dc motor? highlight its significance.
The induced emf developed when the rotating conductors of the armature between the poles of magnet, in a DC motor, cut the magnetic flux, opposes the current flowing through the conductor, when the armature rotates, is called back emf. Its value depends upon the speed of rotation of the armature conductors. In starting, the value of back emf is zero.