# Eg2098 Industrial Electronics & Control

9 Questions | Total Attempts: 41  Settings  Related Topics
• 1.
A shunt DC motor operates at 700 rpm when an armature of 18 A from a 230-V supply. If the armature resistance is 0.25W, calculate the no-load speed, assuming that all output losses are negligible.
• A.

700.0 rpm

• B.

778.5 rpm

• C.

714.0 rpm

• D.

687.2 rpm

• 2.
Find the output torque of a DC motor whose output power is 1200 W and whose shaft speed is 1200 rpm.
• A.

1.00 Nm

• B.

60.0 Nm

• C.

0.105 Nm

• D.

9.55 Nm

• 3.
A 110V series DC motor has an armature resistance of 0.3W and a field resistance of 0.2W. The motor is running off a 110V DC power supply and draws a line current of 20A and rotates at 1500 rpm while driving a mechanical load. The rotational loss of the motor is 250W. Calculate the efficiency of the motor.
• A.

79.55%

• B.

70.45%

• C.

87.5%

• D.

61.36%

• 4.
A 3-phase, 6-pole, induction motor is supplied with a 240V, 50 Hz supply and draws a current of 35A at a power factor of 0.75 and has a full-load slip of 2.0%. The total copper loss and iron loss in the stator is 350W. Calculate the input power, Pin,  of the induction motor.
• A.

14198 W

• B.

10562 W

• C.

10912 W

• D.

14548 W

• 5.
A 4-pole induction motor is energised by 3-phase, 50 Hz supply. The motor (rotor) runs on full-load at 5 percent slip. Determine:-                                        (i)  The speed of the rotating magnetic field (ns)                                        (ii) The frequency of the stator currents (fs)
• A.

1,500 rpm, 50 Hz

• B.

1,500 rpm, 2.5 Hz

• C.

1,425 rpm, 50 Hz

• D.

1,425 rpm, 2.5 Hz

• 6.
A DC shunt motor is connected to 230 V DC power supply. The motor has an armature resistance of 0.8 ohm and a field resistance of 100 ohms. The motor draws a current of 12A and rotates at 300 rpm at full load. Find the input power.
• A.

2760 W

• B.

3000 W

• C.

2880 W

• D.

529 W

• 7.
In the 3-phase induction motor, if the rotor moves at the same speed as the magnetic field
• A.

The slip will be 1

• B.

The torque will be maximum

• C.

The slip will be zero

• D.

The torque will remain unchanged

• 8.
A 100V DC series motor runs at 1500 rpm with a line current of 20A. The armature resistance is 0.3W and the field resistance is 0.2W. Find the power developed.
• A.

1800 W

• B.

1880 W

• C.

1920 W

• D.

2000 W

• 9.
An induction motor is running at a slip of 0.1. The input power is 2000W. The stator copper loss and core loss is 200W. The rotational loss is 50W. What is the rotor copper loss?
• A.

1750W

• B.

180W

• C.

175W

• D.

200W