Salient Pole and Non Salient Pole Synchronous Generator
Table of Contents
Salient Pole and Non Salient Pole of Synchronous Generator
Salient Pole Synchronous Alternator
- Salient pole Generators will have a large diameter and a short axial length.
- Salient Pole shoes cover 2/3 of the pitch
- Eddy currents are minimised by laminating the salient poles.
- And Salient Poles are used in hydraulic turbines or diesel engines
- Since the water turbine’s speed is slow, more poles are needed to achieve the desired frequency. Salient pole machines will therefore typically have between 4 and 60 poles.
- Cheaper compared to cylindrical rotor machines for speeds below 1000rpm.
- Causes excessive windage losses
- Salient pole generators will have typical speed about 100 to 375 rpm.
- Flux distribution is not uniform due to the presence of salient poles, hence emf waveform generated is not good compared to cylindrical machine
- Salient Pole Synchronous Generators are employed in Hydro-Power plants.
Non-Salient pole Synchronous Alternator
- Non-Salient poles are used for High speed operation (typically speed will be 1500 and 3000 rpm)
- Non-Salient pole generators will have smaller diameter and longer axial length
- Better in dynamic balancing because of absence of salient poles.
- Non-Salient pole have Less windage loss
- Robust construction and noiseless operation
- Nearly sinusoidal flux distribution around the periphery, Therefore gives a better emf waveform than salient pole machine
- No need to provide damper windings (except in special case to assist the Synchronising) because the field poles themselves acts as efficient dampers.
- These Generators are used in Thermal, Gas and in Nuclear Power plants.