A 3-phase,  pole, 50 Hz star connected induction motor has the following parameters referred to the stator:

Stator resistance, magnetizing reactance and core loss of the motor are neglected. The motor is run with constant  control from a drive. For maximum starting torque, the voltage and frequency output, respectively, from the drive, is closest to,

A 3-phase, 415 V, 50 Hz induction motor draws 5 times the rated current at rated voltage at starting. It is required to bring down the starting current from the supply to 2 times of the rated current using a 3-phase autotransformer. If the magnetizing impedance of the induction motor and no load current of the autotransformer is neglected, then the transformation ratio of the autotransformer is given by ……………….. (round off to two decimal places).

An 8-pole, 50 Hz. three-phase, slip-ring induction motor has an effective rotor resistance of 0.08 Ω per phase. Its speed at maximum torque is 650 RPM. The additional resistance per phase that must be inserted in the rotor to achieve maximum torque at start is …………… Ω. (Round off to 2 decimal places.)

Neglect magnetizing current and stator leakage impedance. Consider equivalent circuit parameters referred to stator.

A delta connected 3.7kW, 400V (line), three phase, 4-pole, 50-Hz squirrel-cage induction motor has following equivalent circuit parameters per phase referred to the stator:

,,

Neglect shunt branch in the equivalent circuit. The starting line current in amperes (round off to two decimal places) when it is connected to 100V (line), 10Hz, three-phase AC source is ___________.

A star-connected, 12.5kW, 208 V (line), 3-phase, 60 Hz squirrel cage induction motor has following equivalent circuit parameters per phase referred to the stator: , , , . Neglect shunt branch in the equivalent circuit. The starting current (in Ampere) for this motor when connected to an 80 V (line), 20 Hz, 3-phase AC source is ___________.

The starting line current of a 415V, 3-phase, delta connected induction motor is 120A. When the rated voltage is applied to its stator winding. The starting line current at a reduced voltage of 110V, in ampere, is ______________.

A three phase squirrel cage induction motor has a starting current of seven times the full load current and full load slip of 5%.

If an autotransformer is used for reduced voltage starting to provide 1.5 per unit starting torque, the autotransformer ratio (%) should be

A three phase squirrel cage induction motor has a starting current of seven times the full load current and full load slip of 5%.

If a star-delta starter is used to start this induction motor, the per unit starting torque will be

A three phase squirrel cage induction motor has a starting current of seven times the full load current and full load slip of 5%.

If a starting torque of 0.5 per unit is required then the per unit starting current should be

A 3 phase, 4 poles, 400 V, 50 Hz, star connected induction motor has following circuit parameters.  The starting torque when the motor is started direct-on-line is (use approximate equivalent circuit model)

The following starting method for an induction motor is inferior view of the poor starting torque per ampere of the line current drawn:

A 50kVA, 400V, 3-phase, 50Hz squirrel cage induction motor has full load slip of 5%. Its standstill impedance is 0.866 ohms/phase. It is started using a tapped autotransformer. It the maximum allowable supply current at the time of starting is 100A, then calculate the tap position and the ratio of starting torque to full load torque

An induction motor having full load torque of 60Nm when delta-connected develops a starting torque of 120Nm. For the same supply voltage, if the motor is changed to star-connection, the starting torque developed will be

A 3-phase induction motor coupled to a pump is operating at normal speed. If one line gets disconnected, the motor stops. (True=1/False=0)

In a poly-phase squirrel-cage induction motor, increased starting torque can be obtained by

A 5 kW, 400 V, 50 Hz, 4 pole, delta connected three-phase induction motor is supplied by a cable of negligible inductance. On starting the motor using a star-delta starter, it is found that the starting torque is the same on star as well as delta connection, due to the voltage drop in the feeder resistance. The equivalent circuit parameters of the motor are as follows:

Determine the feeder resistance.