Capacitive reactance

capacitancereactance

I'm doing AC theory as an electrical apprentice now, and my lecturer said that inductive reactance and capacitive reactance both work with Faraday's law, or back-EMF, is this correct for capacitive reactance as well?

Best Answer

Faraday's Law deals with induced EMF in a conductor (inductive elements) when exposed to a changing magnetic field. When the term back EMF is used, it implies a conductor rotating in a magnetic field, such as in a motor.

Capacitive elements are not part of Faraday's Law.

The statement by the lecturer about back EMF does imply a motor. In single phase AC motors, a capacitor is used in conjunction with a start winding to generate a torque in the motor in a specific direction so the motor starts rotating in the desired direction.

Maybe the lecturer wasn't clear on how the capacitor works in a motor, or its function in the motor.