MCQ Test-01 on DC Machines

JavaScript isn't enabled in your browser, so this file can't be opened. Enable and reload.

Guidelines for MCQ Test-01
• There are approx 20 questions of total 20marks
• Each question carry 01 marks
• Total duration of the test is 25 Minutes.
• Types of questions will be numerical/theoretical having multiple choice, fill in the blanks, Multiple correct option, match the following types.
• Some Question having more than one correct option ,so tick all correct answers.
• There is no negative marking.

An unsaturated dc shunt motor drives a constant a torque load at a speed at 1000 rpm taking an armature current of 20 A when 230 volt is applied to motor .if the applied voltage is redused to 115V.the motor runs at .

1 point

500 rpm taking an armature current of 20 A.

1000 rpm taking an armature current of 40 A.

1000 rpm taking an armature current of 20 A.

500rpm taking an armature current of 40A.

Clear selection

A dc shunt motor run at 500 rpm at 220 v. a resistance of 4.5Ω is added in series with armature for speed control. The armature resistance is 0.5Ω . the current to stall the motor will be

1 point

44A

44.4A

50A

60A

Clear selection

DC shunt motor runs at a speed of 1,000 rpm on no load taking a current of 6 Amp from supply, when connected to 220 V dc supply. Its full-load current is 50 Amp. Calculate its speed on full-load. Assume Ra = 0.3Ω and Rsh = 110 Ω.

1 point

940 RPM

1000 RMP

900 RPM

960 RPM

1060 RPM

Clear selection

In DC shunt motor

1 point

Both armature & field winding are connected in parallel with a common source

Armature winding is parallel with source

The field winding is parallel with source

Armature and field winding both in series with source

Clear selection

A DC series motor is best suited for electrical traction because:

1 point

It runs at very high speed

It is cheaper in cost

It develops high starting torque

It is more rugged in construction like induction motor

Clear selection

Which are the parts of DC machines

1 point

Commutator

Carbon Brush

Field pole

Armature

Magnetic Frame/Yoke

Can you tell that where DC shunt motors are used

1 point

Where the speed is required to remain constant from no-load to full load-condition

Where large starting torque is required

Where the load fluctuations is more

Where the required torque is high and speed is low at starting

Clear selection

The current drawn by a 120 - V d.c. motor of armature resistance 0.5 Ω and back e.m.f. 110 V is .......... ampere.

1 point

Which motor can be operated on DC as well as AC Supply

1 point

Universal Motor

BLDC Motor

Stepper Motor

Shunt Motor

Clear selection

When load is removed, .......... motor will run at the highest speed.

1 point

differential compound

cumulative-compound

shunt

series

Clear selection

If the field circuit of a loaded shunt motor is suddenly opened

1 point

it would draw abnormally high armature current

torque developed by the motor would be reduced to zero.

it would race to almost infinite speed

circuit breaker or fuse will open the circuit before too much damage is done to the motor

Clear selection

Following characteristics is associated with

2 points

Fig (a)

Fig(b)

Fig(c)

DC shunt motor

DC series motor

With the increase in the speed of a dc motor:

1 point

Back EMF and line current will not change

Back emf falls and line current increases

Back emf increases but the line current falls

Both back emf and line current falls

Both back emf as well as line current increases

Clear selection

Select all correct option with respect to starter required for DC motor

1 point

3 point starter- DC shunt motor

3 point starter- DC series motor

2 point starter- DC series motor

2 point starter- DC shunt motor

When a dc machine is connected to the dc supply main it will produce:

1 point

None of the above

EMF in phase with the applied voltage

EMF decreases with time

EMF in opposition to the applied voltage

Clear selection

A dc series motor develops a torque of 20Nm at 3A of load current. if the current is increased to the 6Athe torque developed will be (Neglect Saturation)

1 point

20Nm

10Nm

40Nm

80Nm

Clear selection

Neglecting saturation, if current taken by a series motor is increased from 10 A to 12 A, the percentage increase in its torque is ........ percent

1 point

30.5

16.6

Clear selection

Lap winding and wave winding are the type of

1 point

Field winding

Armature winding

Stator winding

None of the above

Clear selection

A lap wound dc machine has 400 conductors and 8 poles. The voltage induced per conductor is 2 volt. The machine generates a voltage of

1 point

100V

800V

300V

400V

200V

Clear selection

Submit

Clear form

Never submit passwords through Google Forms.

Forms

This content is neither created nor endorsed by Google.