**1. **A dc shunt motor has the following characteristics, Ra = 0.5 Ω, Rf = 200 Ω, base speed = 1000 rpm, rated voltage = 250 V. On no-load, it draws a current = 5 A. At what speed will this run while delivering a torque of 150 N.m?

**2.** A 4-pole dc motor takes a 50 A armature current. The armature has lap-connected 480 conductors. The flux per pole is 20 mWb. Calculate the gross torque developed by the armature of the motor.

- 52.6 N-m
- 39.5 N-m
- 76.4 N-m
- 15.2 N-m

**3.** With an armature voltage of 100 V and rated field winding voltage, the speed of a separately excited DC motor driving a fan is 1000 rpm, and its armature current is 10 A. The armature resistance is 1 Ω. The load torque of the fan load is proportional to the square of the rotor. Neglecting rotational losses, the value of the armature voltage (in Volt) which will reduce the rotor speed to 500 rpm is

- 50 V
- 45.5 V
- 30 V
- 47.5 V

**4.** A DC shunt machine develops an AC EMF of 250 V at 1500 rpm. Find the torque developed for an armature current of 50 A.

- 59.6 N-m
- 79.6 N-m
- 69.6 N-m
- 49.6 N-m

**5.** An Electric motor, developing a starting torque of 15 Nm, starts with a load torque of 7 Nm on its shaft. If the acceleration at start is 2 rad/s^{2}, the moment of inertia of the system is (neglecting viscous and Coulomb friction)

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

- 44%
- 40%
- 20%
- 16%

**7.** A DC motor has the following specifications: 10 hp, 37.5 A, 230 V; flux / pole = 0.01 Wb, number of poles = 4, number of conductors = 666, number of parallel paths = 2. Armature resistance = 0.267Ω. The armature reaction is negligible and rotational losses are 600W. The motor operates from a 230V DC supply. If the motor runs at 1000 rpm, the output torque produced in (in Nm) is _______

- 60.34 Nm
- 57.78 Nm
- 51.34 Nm
- 40.23 Nm

**8.** A DC Motor develops a torque of 150 N-m. A 10 percent reduction in the field flux causes a 50 percent increase in armature current. The new value of torque is:

- 102.5 N-m
- 202.5 N-m
- 172.5 N-m
- 232.5 N-m

**9.** A shunt–connected DC motor operates at its rated terminal voltage. Its no-load speed is 200 radians/second. At its rated torque of 500 Nm, its speed is 180 radian/second, The motor is used to directly drive a load whose load torque TL depends on its rotational speed (in radian/second), such that TL = 2.78 × ω_{T}. Neglecting rotational losses, the steady-state speed (in radian/second) of the motor, when it drives this load is __________

- 180 rad/sec
- 260 rad/sec
- 360 rad/sec
- 90 rad/sec

**10.** Which of the given options is correctly represented by the following expression? 9.55 (output / N), where N is in rpm?

- Back EMF
- Maximum efficiency
- Armature torque
- Shaft torque