What is the relation of the copper loss and brush contacts with the total loss in universal commutator motors?

Copper loss, brush contact loss, and total loss in universal commutator motors are interrelated as they contribute to the overall efficiency and performance of the motor.

1. Copper Loss: This refers to the energy lost as heat in the motor windings due to the resistance of the copper wire when current flows through it. It can be calculated using the formula ( P_{text{copper}} = I^2R ), where ( I ) is the current and ( R ) is the resistance of the windings. Copper losses increase with higher loads and are a significant component of the total losses in the motor.

2. Brush Contact Loss: This is the loss of energy that occurs at the brush-commutator interface due to contact resistance, friction, and sparking. Brush contact losses can cause additional heating and reduce the efficiency of the motor. These losses depend on the quality of brushes used, the current passing through them, and the contact pressure.

3. Total Loss: The total loss in a universal commutator motor is the sum of all losses occurring in the motor, including copper losses, brush contact losses, iron losses (core losses due to magnetic hysteresis and eddy currents), and mechanical losses (due to friction and windage).

The relation among these losses can be summarized as follows: both copper losses and brush contact losses contribute to the total losses, affecting the overall efficiency. Reducing either type of loss (e.g