Circle Diagram of Induction Motor — Lesson 4

This lesson covers the concept of the circle diagram of a three-phase induction motor. It begins with the verification of an RL circuit excited by a fixed voltage at a fixed frequency. The lesson explains that if the resistance varies from 0 to infinity, the locus of the tip of the current phasor forms a circle. The diameter of this circle is V/X, where X is the inductive reactance. The lesson further elaborates on the points where R equals 0 and infinity, explaining their implications on the current drawn by the circuit.

Video Highlights

00:25 - Introduction to the circle diagram of a three-phase induction motor
02:26 - Equivalent circuit of induction motor without stator impedance
19:08 - Circle diagram of induction motor without stator loss

Key Takeaways

- In an RL circuit excited by a fixed voltage at a fixed frequency, the locus of the tip of the current phasor forms a circle if the resistance varies from 0 to infinity.
- The diameter of this circle is V/X, where X is the inductive reactance.
- When R equals 0, the current will be V/X lagging V by 90 degrees, and when R equals infinity, the current drawn will be 0.