What is the difference between salient and non-salient pole rotor?

Salient pole rotors have large diameter and shorter axial length. Flux distribution is relatively poor than non-salient pole rotor, hence the generated emf waveform is not as good as cylindrical rotor. Salient pole rotors generally need damper windings to prevent rotor oscillations during operation.

What is the difference between salient and non-salient pole in an alternator?

Non-Salient pole generators will have smaller diameter and longer axial length. They are used for High speed operation (typically speed will be 1500 and 3000 rpm) Better in dynamic balancing because of absence of salient poles. Non-Salient pole generators are used in Thermal,Gas and in Nuclear Power plants.

Why salient pole rotor is not used for high speed?

The term salient means projected outward. Hence poles of salient type rotor are projected out from the surface of core and houses the rotor field winding. Construction of salient type rotor is not strong enough to withstand mechanical stresses due to which this type of rotor cannot run at higher speed.

Why salient pole rotor is laminated?

Lamination is done in any machine to reduce the effect of eddy current loss. Eddy Current can be induced within nearby stationary conductors by a time-varying magnetic field created by an AC source only(Not DC ). Since Rotor of the cylindrical synchronous machine is excited by DC supply,so the rotor flux is DC.

What is salient pole type rotor?

Salient pole type of rotor consist of large number of projected poles (salient poles) mounted on a magnetic wheel. They are larger in diameter and smaller in axial length. Non-salient pole rotors are cylindrical in shape having parallel slots on it to place rotor windings.

Why are round rotor synchronous machines used at high speeds?

Since the rotor can be balanced easily and centrifugal forces will be evenly distributed, the rotor of the round (cylindrical) rotor generator can be run at higher rotational speed.

How does a salient pole rotor work?

Salient pole rotor Direct current (DC), from an external exciter or from a diode bridge mounted on the rotor shaft, produces a magnetic field and energizes the rotating field windings and alternating current energizes the armature windings simultaneously.

In which applications round or cylindrical rotor and salient rotor synchronous machines are used?

Round-Rotor Machines Machines with cylindrical rotors are typically found in higher speed higher power applications such as turbogenerators. Using 2 or 4 poles, these machines rotate at 3600 or 1800 rpm (with 60hz systems). Remember that machine power is a function of the size of the machine.

What are the main differences between cylindrical rotor and salient pole rotor synchronous generators?

In general, the Cylindrical Rotor type machines are confined to 2 and 4 pole turbine generators, while salient pole types are built with 4 poles upwards and include most classes of duty. Both classes of machine are similar in Stator construction point of view.

What is the difference between salient pole and non-salient pole rotors?

Windage loss as well as noise is less as compared to salient pole rotors. Their construction is robust as compared to salient pole rotors. Number of poles is usually 2 or 4. Damper windings are not needed in non-salient pole rotors. Flux distribution is sinusoidal and hence gives better emf waveform.

Why damper windings are not needed in non-salient pole rotors?

Damper windings are not needed in non-salient pole rotors. Flux distribution is sinusoidal and hence gives better emf waveform. Non-salient pole rotors are used in nuclear, gas and thermal power plants.

What is the difference between turbo generator and salient pole generator?

It shall also be noted that Salient Pole machines cannot be used at higher speed because at higher speed the centrifugal forces will be large which may damage the Salient pole bolted on the Rotor core. This is why Turbo Generators uses Cylindrical Pole construction whereas Hydro generators use Salient Pole construction.

What are the different types of rotors of an electrical machine?

Rotors of an electrical machine are classified as: (i) Salient pole rotors and (ii) Non-salient pole rotors. Both types are explained below. In salient pole type of rotor consist of large number of projected poles (salient poles) mounted on a magnetic wheel.