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 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
A phase sequence is an order or sequence in which the currents or voltages of different phases attain their maximum values. In a three-phase system, there are only two possible phase sequences: R-Y-B (positive Phase Sequence) and R-B-Y (Negative Phase Sequence).
This type of motor is designed to operate with the start winding and it’s series capacitor permanently connected to the supply. lt has two capacitors connected in parallel in the start winding circuit for starting purposes. The running capacitor is employed to correct the power factor. As a result, this motor has a higher starting torque as well as a higher efficiency. These motors are employed in sizes ranging from 375 W to 7.5 kW. The power factor of these motor is upto 80% to 100%.
EXAMIANS
