In a shunt motor, torque is proportional to which of the following?

In a shunt motor, the torque output is primarily proportional to the armature current. This relationship stems from the fundamental principles of electromagnetism that govern electric motor operation. In a shunt motor, the field winding is connected in parallel (or shunt) to the armature winding. As the armature current increases, the magnetic field generated by the armature also increases, which enhances the overall torque produced by the motor.

The torque generated in the motor can be expressed by the equation:

[ T \propto \phi \times I_a ]

where ( T ) is the torque, ( \phi ) is the magnetic flux, and ( I_a ) is the armature current. In a shunt motor, the field current remains relatively constant, as it is determined by the supply voltage and the resistance of the field winding. Therefore, any increase in the armature current directly translates to an increase in torque, making it a critical factor in determining the motor's performance under varying load conditions.

Understanding this relationship is pivotal for effective control and operation of shunt motors in practical applications, particularly in scenarios where torque demands fluctuate.