In motor applications, efficiency of the motor is always less than 100% due to conversion of the _____.

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SSC JE Electrical 9 Oct 2023 Shift 3 Official Paper-I

Answer 1

Electrical Motor

An electric motor is an electric machine that converts electrical energy into mechanical energy.
Most electric motors operate through the interaction between the motor’s magnetic field and electric current in a wire winding.
This interaction generates a force (as per Faraday’s Law) in the form of torque which is applied to the motor’s shaft.
Since the input energy is converted into heat, there are mechanical losses such as friction and windage loss at the motor's shaft due to which the efficiency of the motor is always less than 100%.
The efficiency of electrical motors being less than 100% is consistent with the Law of Conservation of Energy. The Law of Conservation of Energy states that energy cannot be created or destroyed, only transformed from one form to another.
In the case of electrical motors, some of the electrical energy is inevitably converted into other forms of energy, such as heat and sound, due to factors like friction and resistance in the motor's components.
This loss of energy reduces the overall efficiency of the motor, but it does not violate the Law of Conservation of Energy because the total amount of energy in the system remains constant.