High Efficiency DC Motor: A Closer Look

What is the efficiency of a 10 hp DC motor that draws 31 amps at 300 volts?

How to calculate the efficiency of a motor?

Answer:

The efficiency of a 10 hp DC motor that draws 31 A at 300 volts is equal to 80%.

Efficiency is an important factor to consider when evaluating the performance of an electric motor. In the case of a 10 hp DC motor drawing 31 amps at 300 volts, the efficiency is calculated as follows:

Given data:

• Horsepower of the DC motor = 10 hp
• Current drawn by the motor = 31 A
• Voltage supply to the motor = 300 V

To calculate the efficiency of the motor, we need to determine the mechanical power output and the electrical power input to the motor. The efficiency can be derived from the ratio of the output power to the input power, expressed as a percentage.

First, convert the horsepower to watts:

1 hp = 745.7 W

Output power = 10 hp = 10 × 745.7 = 7457 W

Input power = 31 A × 300 V = 9300 W

Now, calculate the efficiency of the motor:

Efficiency = (Output Power / Input Power) × 100

Efficiency = (7457 / 9300) × 100 = 80%

Therefore, the efficiency of the 10 hp DC motor drawing 31 A at 300 V is 80%. This means that 80% of the electrical power input is successfully converted into mechanical power output by the motor.