In case of a slip ring induction motor, external resistors are connected in the rotor circuit to __________ the starting torque and to __________ the starting current form the supply, respectively.

The correct answer is option 2): (increase, decrease)

Concept:

• An induction motor is an electrical device that converts electrical energy into mechanical energy.
• It is most widely used for industrial applications due to its self-starting attribute.
• Slip ring induction motor is one of the types of 3-phase induction motor and is a wound rotor motor type.
• Because of various advantages like low initial current, high starting torque, and improved power factor, it is used in applications that require high torque, cranes, and elevators.
• The rotor windings consist of more number of windings, higher induced voltage, and less current compared to the squirrel-cage rotor.
• In case of a slip ring induction motor, external resistors are connected in the rotor circuit to increase  the starting torque and to decrease  the starting current form the supply, respectively.
• The windings are connected to external resistance through slip rings, which helps to control the torque/speed of a motor.
• The external resistance reduces high resistance as soon as the motor obtains normal speed and increases the starting torque of a motor.
• The tweaking of external resistance also aids in decreasing of rotor and stator current but improves the power factor of a motor.