Crompton Greaves Motor

Max speed is defined by the bus voltage and the voltage constant (Ke). The max speed is simply when current flowing is zero, and speed = Vbus/ Ke. The units for Ke for linear motors is v/m/sec and for rotary and arc v/rad/sec.A 3 phase induction motor derives its name from the fact that the rotor current is induced by the magnetic field, instead of electrical connections. The operating principle of a 3 phase induction motor is based on the production of a rotating magnetic field.The rated full load speed, or rpm (revolutions per minute) of a motor is the speed at which the motor will operate under full torque conditions when applied voltage and frequency are held constant at the rated values.Most electric motors are designed to run at 50% to 100% of rated load. Maximum efficiency is usually near 75% of rated load. Thus, a 10-horsepower (hp) motor has an acceptable load range of 5 to 10 hp; peak efficiency is at 7.5 hp. A motor's efficiency tends to decrease dramatically below about 50% load.