1. The frame of an induction motor is made of carbon (a) closed grained cast iron (b) aluminium (c) stainless steel 2. Slip rings for induction motors are made of (a) phosphor bronze (b) aluminium (c) carbon (d) cobalt steel 3 . If ‘s’ is the slip and ‘f’ is the supply frequency, the frequency […]
1. In induction motor, percentage slip depends on (a) supply frequency (b) supply voltage (c) copper losses in motor (d) none of the above 2.The efficiency of an induction motor ……….is than that of a transformer. (a) lower (b) higher (c) either of the above (d) none of the above 3.If the rotor circuit of
1. In a megger when not in operation, the needle shows a resistance of (a) Zero ohms (b) Infinity (c) 100 ohms (d) 500 Ohms 2. A cadmium sulphide cell is a (a) solar cell (b) dry cell (c) photo voltaic cell (d) photo conductive cell. 3. A photo electric transducers are used for the
1. Bolometers are used for the measurement of (a) optical inputs (b) thermal radiations (c) electrical signals (d) temperature inputs. 2. A bolometer is an element which (a) senses optical input and delivers thermal output (b) senses thermal inputs (c) senses electrical input and delivers thermal output (d) senses optical input and delivers electrical output.
1. A pointer of an instrument once deflected returns to zero position, when the current is removed, due to (a) action of gravity (b) mass of the pointer (c) controlling torque (d) damping torque 2. An instrument in which the value of electrical quantity to be measured can be determined from the deflection of the
1. In which of the following cases shunt capacitance is negligible ? (a) Short transmission lines (b) Medium transmission lines (c) Long transmission lines (d) All transmission lines 2. A lightning arrester is usually located nearer to (a) transformer (b) isolator (c) bus-bar (d) circuit breaker (e) none of the above 3. The material used
1. Which of the following has least effect on corona ? (a) Atmospheric temperature (b) Number of ions (c)Site and charge per ion (d) Mean free path 2. In context of corona, if the conductors are polished and smooth, which of the following statements is correct ? (a) Hissing sound will be more intense (b)
1.For aluminum, as compared to copper, all the following factors have higher values except (a) specific volume (b) electrical conductivity (c) co-efficient of linear expansion (d) resistance per unit length for same cress-section 2.Which of the following equipment, for regulating the voltage in distribution feeder, will be most economical ? (a) Static condenser (b) Synchronous
1. For an overhead line, the surge impedance is taken as (a) 20 – 40 ohm. (b) 70 – 80 ohms (c) 100 – 200 ohms (d) 500 -1000 ohms 2. The presence of ozone due to corona is harmful because it (a) reduces power factor (b) corrodes the material (c) transfer energy to the
1. ……………. are the conductors, which connect the consumer’s (a) terminals to the distribution (b) Distributors (c) Service mains (d) Feeders (e) None of the above 2. The underground system cannot be operated above (a) 440 V (b) 11 kV (c) 33 kV (d) 66 kV 3. The usual spans with R.C.C. poles are (a)