Determine the efficiency of a 1500kVA, 2300 V, 3 –phase, Y – connected alternator which operates at rated output with a power factor of 80%. The DC armature resistance at 70º C between terminals is 0.08 ohm. The field takes 70 A at 120 V from the exciter equipment. Friction and windage losses are 15kW, iron loss is 35kW and stray load losses is 15 kW. Assume the effective armature winding resistance is 1.5 times the DC value. a. 94.56 % b. 90.31 %
Synchronous Generator
In comparison to an asynchronous generator, it is a machine where the rotor speed is equal to the rotating magnetic field produced by the stator, i.e., mechanical speed is equal to the electrical speed, thus called synchronous, and not asynchronous.
Salient Pole Rotor
Salient pole rotor includes a large number of exposed poles mounted on a magnetic wheel. The construction of a bright pole is as shown in the image on the left. The proposed poles are made of metal laminations. The rotor winding is provided on these poles and is supported by pole shoes.
Determine the efficiency of a 1500kVA, 2300 V, 3 –phase, Y – connected alternator which operates at rated output with a power factor of 80%. The DC armature resistance at 70º C between terminals is 0.08 ohm. The field takes 70 A at 120 V from the exciter equipment. Friction and windage losses are 15kW, iron loss is 35kW and stray load losses is 15 kW. Assume the effective armature winding resistance is 1.5 times the DC value.
a. 94.56 % b. 90.31 %
b. 93.35 % d. 92.62 %
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