A 4-pole, 250V, 120kW, DC short shunt compound generator has the following parameters: Ra=0.015 Ω, Rse=0.01 Ω, Rf =125 Ω, flux per pole=3x10^6 maxwells, Speed=1000rpm, hysteresis loss=2.5kW, eddy current loss=1.5kW, total mechanical loss=5kW. At what speed and excitation does this generator needs to operate in order to maintain an overall efficiency of 88%. Note: Excitation needs to be adjusted with speed in order to generate the same emf.
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.
A 4-pole, 250V, 120kW, DC short shunt compound generator has the following parameters: Ra=0.015 Ω, Rse=0.01 Ω, Rf =125 Ω, flux per pole=3x10^6 maxwells, Speed=1000rpm, hysteresis loss=2.5kW, eddy current loss=1.5kW, total
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