Engineering Jobs   »   Electrical Concept Booster   »   Synchronous machine rotor construction

Daily Concept Booster Electrical Engineering: Rotor Construction of 3-Phase Synchronous Machine

Rotor Construction of 3-Phase Synchronous Machine


Rotors of an electrical machine are classified as:
Salient pole rotors and
Non-salient pole rotors.

Salient-pole rotor

The term salient means ‘projecting’. A salient pole consists of poles that are projected out from the surface of the rotor core. These are used for the rotors for four or more poles.
A non-uniform air gap accompanies a salient-pole synchronous machine.

The air gap is minimum under the pole centers, and it is maximum in between the poles. The pole faces are so shaped that the radical air gap length increases from the pole center to the pole tips so that the flux distribution in the air gap is sinusoidal. This will help the machine to generate sinusoidal e.m.f.

Cylindrical Rotor or Non-salient pole rotors

Cylindrical-rotor machines are also known as non-salient pole rotor machines. The construction of the rotor is such that it forms a smooth cylinder. It has no physical poles as in the salient-pole construction. These rotors are made up of solid forgings of high-grade nickel-chrome-molybdenum steel.

Important Note

3-phase synchronous machine rotor construction:
Salient pole rotor: larger diameter, shorter axial length
Cylindrical pole rotor: smaller diameter, larger axial length


Boost your preparation with the all-new Concept Booster Series by Adda247 Engineering Jobs, this series aims to target all the important engineering exams such as SSC JE 2022, GATE 2022, ESE 2022, and many more. Please reach out to us with your feedback in the comment section.

Sharing is caring!

Thank You, Your details have been submitted we will get back to you.

Leave a comment

Your email address will not be published.