The commutator is a feature of d.c.motors. But a.c. motors having wound rotor with brushes and commutator arrangements, are called commutator motors that work on single-phase a.c. supply. The commutator arrangement present in these motors is similar to the armature of a d.c. motor.E.g. of single-phase commutator type induction motor is Repulsion Motor Repulsion-Induction Motor AC Series Motor Universal Motor
The permeance of the magnetic circuit is defined as the reciprocal of the reluctance. Permeance = 1/Reluctance It is defined as the property of the magnetic circuit due to which it allows the flow of the magnetic flux through it. Permeance is analogous to conductance in an electric circuit.
In the PMMC type instrument, the deflection is directly proportional to the current flowing through the instrument, we get a uniform scale for the instrument. It gives a uniform scale of upto 270° or more. Td ∝ I
The maximum power transfer theorem states that the DC voltage source will deliver maximum power to the variable-load resistor only when the load resistance is equal to the source resistance. Similarly, this theorem states that the AC voltage source will deliver maximum power to the variable complex load only when the load impedance is equal to the complex conjugate of the source impedance. Hence when Ri = RL the transfer of power will be maximum.
EXAMIANS