## Marks 1

The frequencies of the stator and rotor currents flowing in the three-phase 8-pole induction motor are 40 Hz and 1 Hz, respectively. The motor speed, ...

A 4-pole induction motor with inertia of 0.1 kg-m2 drives a constant load torque of 2 Nm. The speed of the motor is increased linearly from 1000 rpm t...

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 curren...

A 3-phase, 4-pole, 400 V, 50 Hz squirrel-cage induction motor is operating at a slip of 0.02. The
speed of the rotor flux in mechanical rad/sec, sense...

A 4 pole induction machine is working as an induction generator. The generator supply
frequency is 60 Hz. The rotor current frequency is 5 Hz. The mec...

The direction of rotation of a single-phase capacitor run induction motor is reversed by

In a constant V/f induction motor drive, the slip at the maximum torque

The figure shows the per-phase equivalent circuit of a two-pole three-phase induction motor operating at 50 Hz. The 'air-gap' voltage, Vg across the m...

A single phase induction motor is provided with capacitor and centrifugal switch in series
with auxiliary winding. The switch is expected to operate a...

The torque-speed characteristics of motor ($$T_M$$) and load ($$T_L$$) for two cases are shown in the
figures (a) and (b). The load torque is equal to...

A three-phase, 4-pole, self excited induction generator is feeding power to a load at a
frequency $$f_1$$. If the load is partially removed, the frequ...

In a constant V/f control of induction motor, the ratio V/f is maintained constant from 0 to
base frequency, where V is the voltage applied to the mot...

An 8-pole, 3-phase, 50 Hz induction motor is operating at a speed of 700 rpm. The frequency
of the rotor current of the motor in Hz is ________.

Leakage flux in an induction motor is

The slip of an induction motor normally does not depend on

A balanced three-phase voltage is applied to a star-connected induction motor, the
phase to neutral voltage being V. The stator resistance, rotor resi...

For an induction motor, operating at a slip 's', the ratio of gross power output to
air gap power is equal to:

On the torque/speed curve of induction motor shown in Fig, four points of
operation are market as W, X, Y and Z. Which one of them represents the
oper...

The type of single-phase induction motor having the highest power factor at full
load is

The direction of rotation of a 3-phase induction motor is clockwise when it is
supplied with 3-phase sinusoidal voltage having phase sequence A-B-C. F...

For a linear electromagnetic circuit, the following statement is true.

Group I lists different applications and Group II lists the motors for these
applications. Match the application with the most suitable motor and choo...

No-load test on a 3-phase induction motor was conducted at different supply
voltages and a plot of input power versus voltage was drawn. This curve wa...

If a 400 V, 50 Hz, star connected, 3 phase squirrel cage induction motor is
operated from a 400 V, 75 Hz supply, the torque that the motor can now pro...

Starting torque can be obtained in the case of a single phase induction motor
with identical main and auxiliary windings by connecting

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

A 3-phase squirrel cage induction motor has a full load efficiency of 0.8 and a
maximum efficiency of 0.9. It is operated at a slip of 0.6 by applying...

If an induction machine is run at above synchronous speed, it acts as

Unbalanced supply voltage given to a $$3-$$ phase, data-connected induction motor will cause

When the supply voltage to an induction motor is reduced by $$10\% $$, the maximum torque will decrease by approximately

In case of a split phase motor, the phase shift between currents in the two windings is around

An induction motor having full load torque of $$60$$ $$Nm$$ when delta-connected develops a starting torque of $$120$$ $$N$$-$$m.$$ For the same simpl...

In an induction motor, if the air gap is increased

An induction motor is fed from a balanced three phase supply at rated voltage
and frequency through a bank of three single phase transformers connecte...

Skew is used in induction motors in order to reduce torque due to

A three phase slip ring induction motor is fed from the rotor side with stator winding short circuited. The frequency of the currents flowing in the s...

## Marks 2

The equivalent circuit of a single phase induction motor is shown in the figure, where the
parameters are
R1 = R2' = Xl1 = Xl2' = 12 $$\Omega $$, Xm =...

A star-connected, 12.5 kW, 208 V (line), 3-phase, 60 Hz squirrel cage induction motor has
following equivalent circuit parameters per phase referred t...

A 375W, 230 V, 50 Hz capacitor start single-phase induction motor has the following constants
for the main and auxiliary windings (at starting): $$Z_m...

A 220 V, 3-phase, 4-pole, 50 Hz inductor motor of wound rotor type is supplied at rated voltage and frequency. The stator resistance, magnetizing reac...

A 3-phase 50 Hz square wave (6-step) VSI feeds a 3-phase, 4 pole induction motor. The VSI line voltage has a dominant 5th harmonic component. If the o...

A three-phase slip-ring induction motor, provided with a commutator winding, is shown in
the figure. The motor rotates in clockwise direction when the...

A 3 phase, 50 Hz, 6 pole induction motor has a rotor resistance of 0.1 Ω and reactance of
0.92 Ω. Neglect the voltage drop in stator and assume that t...

A 4-pole induction motor, supplied by a slightly unbalanced three-phase 50Hz
source, is rotating at 1440 rpm. The electrical frequency in Hz of the in...

The locked rotor current in a 3-phase, star connected 15 kW, 4-pole, 230 V, 50 Hz induction motor
at rated conditions is 50 A. Neglecting losses and m...

A three-phase 440V, 6 pole, 50Hz, squirrel cage induction motor is running at a
slip of 5%. The speed of stator magnetic field to rotor magnetic field...

A $$200$$ $$V,$$ $$50$$ $$Hz,$$ single-phase induction motor has the following connection diagram and winding orientations shown. $$MM'$$ is the axis ...

A $$230V,$$ $$50Hz,$$ $$4$$ pole, single phase induction motor is rotating in the clockwise (forward) direction at a speed of $$1425$$ $$rpm.$$ If the...

A $$400$$ $$V,$$ $$50$$ $$Hz$$, $$4$$ pole, $$1400$$ $$rpm$$, star connected squirrel cage induction motor has the following parameters referred to t...

A $$400$$ $$V,$$ $$50$$ $$Hz,$$ $$30$$ $$hp,$$ three-phase induction motor is drawing $$50$$ A current at $$0.8$$ power factor lagging. The stator and...

A $$3$$-phase, $$440$$ $$V,$$ $$50$$ $$Hz,$$ $$4$$ pole, slip ring induction motor is feed from the rotor side through an auto transformer and the st...

A $$3$$-phase, $$440$$ $$V,$$ $$50$$ $$Hz,$$ $$4$$ pole, slip ring induction motor is feed from the rotor side through an auto transformer and the st...

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 auto-tra...

A three-phase squirrel cage induction motor has a starting torque of $$150\% $$ and a maximum torque of $$300\% $$ with respect to rated torque at rat...

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-delt...

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 ...

A $$3$$ phase, $$4$$ pole, $$400$$ $$V,$$ $$50$$ $$Hz,$$ star connected induction motor has following circuit parameters $${r_1} = 1.0\Omega ,\,{r_2} ...

The speed of a $$4$$-pole induction motor is controlled by varying the supply frequency while maintaining the ratio of supply voltage to supply freque...

A $$3$$ phase, $$10$$ $$kW$$, $$400$$ $$V,$$ $$4$$ pole, $$50$$ $$Hz$$, star connected induction motor draws $$20$$ A on full load. Its no load and bl...

Under no load condition, if the applied voltage to an induction motor is reduced
from the rated voltage to half the rated value,

A three-phase cage induction motor is started by direct-on-line (DOL) switching
at the rated voltage. If the starting current drawn is 6 times the ful...

Assertion [a]: Under V/f control of induction motor, the maximum value of the
developed torque remains constant over a wide range of speed in the subs...

In a single phase induction motor driving a fan load, the reason for having a high
resistance rotor is to achieve

A single-phase, 230 V, 50 Hz, 4 pole, capacitor-start induction motor has the
following stand still impedances
Main winding Zm =6.0 + j4.0Ω
Auxiliary ...

A rotating electrical machine having its self-inductances of both the stator and
the rotor windings, independent of the rotor position will be definit...

A 400 V, 15 kW, 4 pole, 50 Hz, Y-connected induction motor has full load slip of
4%. The output torque of the machine at full load is

Following are some of the properties of rotating electrical machines
P. Stator winding current is dc, rotor-winding current is ac
Q. Stator winding cu...

A 3-phase Inductor Motor is driving a constant torque load at rated voltage and
frequency. If both voltage and frequency are halved, following stateme...

A single phase induction motor with only the main winding excited would exhibit
the following response at synchronous speed

When Stator and Rotor windings of a 2-pole rotating electrical machine are
excited, each would produce a sinusoidal mmf distribution in the air gap wi...

A three phase, wound rotor induction motor is to be operated with slip energy
recovery in the constant torque mode, when it delivers an output power P...

The power input to a 415 V, 50 Hz, 6 pole, 3-phase induction motor running at
975 rpm is 40 kW. The stator losses are 1kW and friction and windage los...

A 3-phase, 4-pole squirrel cage induction motor has 36 stator and 28 rotor slots.
The number of phases in the rotor is: