Electromagnet moving coil instrument - EMMC

 EMMC - Electromagnet moving coil instrument 

This instrument will measure the power.

This instrument is also called the Dynamometer type instrument or Transfer type instrument.

It has two coils fixed and a moving coil as shown in the figure.

It works on the principle of Faraday's laws of electromagnetic induction.

Relation between the input current and the deflection torque:

At steady state, the deflection torque is equal to the controlling torque so we get the deflection torque as,

As the current splits in the pressure coil and the current coil, we take the current with the phase shift,