The melting point of Eureka is 1221 to 1300 °C The melting point of Kanthal is 1,425 °C The melting point of Nichrome is 1400 °C The melting point of Graphite is 3,600°C Hence Eureka has the least range of temperature.
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.
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
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