The correct answer is: B. The speed will increase in proportion to reduction in load.
A DC shunt motor is a type of DC motor that uses a shunt field winding to create a magnetic field that interacts with the armature winding to produce torque. The shunt field winding is connected in parallel with the armature winding, which means that it always has the same current flowing through it. This results in a constant magnetic field, which in turn results in a constant torque.
When the load on a DC shunt motor is reduced, the current through the armature winding decreases. This causes the magnetic field to weaken, which in turn causes the torque to decrease. However, the decrease in torque is not proportional to the decrease in load. This is because the shunt field winding still has the same current flowing through it, which means that it still produces a magnetic field. This magnetic field helps to keep the motor running, even when the load is reduced.
As a result, the speed of a DC shunt motor will increase in proportion to the reduction in load. This is because the decrease in torque is not proportional to the decrease in load. The shunt field winding still produces a magnetic field, which helps to keep the motor running, even when the load is reduced.
Here are brief explanations of each option:
- Option A: The speed will increase abruptly. This is not correct because the speed of a DC shunt motor will increase in proportion to the reduction in load, not abruptly.
- Option B: The speed will increase in proportion to reduction in load. This is the correct answer.
- Option C: The speed will remain almost/constant. This is not correct because the speed of a DC shunt motor will increase in proportion to the reduction in load.
- Option D: The speed will reduce. This is not correct because the speed of a DC shunt motor will increase in proportion to the reduction in load.