QUESTIONS CARRY TWO MARKS EACH.
A 3-phase 4-pole alternator has 48 stator slots carrying the 3-phase distributed winding. Each coil of the winding is short chorded by one slot pitch. The winding factor is given by
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Solution
A transmission line conductor at a river crossing is supported from two towers at heights of 30 m and 90m above water level. The horizontal distance between towers is 270 m, if tension in the conductor is 1800 kg and conductor weight 1 kg/m. What is the clearance between conductor and the water at a point midway between the towers?
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A transmission line has a span of 275 m between level supports. The conductor has a diameter of 19.53mm, weight 0.844 kgf/m and has an ultimate breaking strength of 7950kg f. Each conductor has a radial covering of ice 9.53 mm thick and is subjected to a horizontal wind pressure of 40kgf/m2 of ice covering projected area. If the factor of safety is 2, what is the deflected sag? Ice weight is 913.5 kgf/m3.
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A dc battery of 50 V is charged through a 10 Ω resistor as shown in the figure. Assume that the thyristor is continuously fired. The average value of charging current is
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In the bridge circuit shown below, at balance condition, the value of Cs= 0.5 μF and Rs= 1000 Ω.
The values of inductance Lx and resistance Rx are
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For the Owen-bridge circuit shown below, when balanced,the values of L and R are
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In the circuit shown in Figure, L is large and the average value of I0 is 100 A. Then which of the following is true for the circuit?
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In a DC machine, which of the following statements is true?
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In a DC machine, the effect of armature reaction under pole shoe can be neutralized by using compensating winding because compensating winding neutralizes the armature flux. While interpole winding is used for improving commutation, i.e.,sparkless commutation.
In a transformer,zero voltage regulation at full load is
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A single phase full-wave half-controlled bridge converter feeds an inductive load. The two SCRs in the converter are connected to a common DC bus. The converter has to have a freewheeling diode.
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Solution
Single phase full wave half controlled bridge converter feeds an inductive load. The two SCRs in the converter re connected to a common dc bus.The converter has to have free wheeling diode because the converter does not provide for freewheeling for high values of triggering angles.