Motor Winding Resistance Calculator

Motor Winding Resistance (ohms):


About Motor Winding Resistance Calculator (Formula)

A Motor Winding Resistance Calculator is a practical tool used in the field of electrical engineering and motor design and maintenance to calculate the electrical resistance of the windings within an electric motor. The winding resistance is a crucial parameter that impacts the motor’s efficiency, performance, and heating characteristics. This calculator assists engineers and technicians in assessing the motor’s health, diagnosing potential faults, and ensuring it operates within safe limits.

Formula for Calculating Motor Winding Resistance:

The electrical resistance of a motor winding can be calculated using Ohm’s Law, which relates resistance (R), voltage (V), and current (I):

Winding Resistance (R) = Voltage Across the Winding (V) / Current Through the Winding (I)


  • Winding Resistance (R) is the resistance of the motor winding, typically measured in ohms (Ω).
  • Voltage Across the Winding (V) is the voltage applied across the motor winding during the measurement, usually measured in volts (V).
  • Current Through the Winding (I) is the current passing through the motor winding during the measurement, typically measured in amperes (A).

To determine the winding resistance, the motor should be de-energized and disconnected from the power source. The resistance measurement can be made using specialized equipment like an ohmmeter or multimeter, which applies a known voltage and measures the resulting current. The winding resistance is calculated as the voltage applied divided by the measured current.

Importance of Motor Winding Resistance:

  1. Efficiency Assessment: The winding resistance affects the motor’s overall efficiency. Higher resistance results in more power loss in the form of heat, reducing the motor’s efficiency. By monitoring the winding resistance, engineers can assess whether the motor is operating optimally.
  2. Fault Detection: Changes in winding resistance can indicate potential motor faults, such as damaged windings, loose connections, or contamination. An increase in resistance may suggest insulation breakdown, while a decrease could be due to shorted turns.
  3. Temperature Rise Estimation: Knowing the winding resistance allows engineers to estimate the motor’s temperature rise during operation. Excessive heating can lead to insulation degradation and motor failure.
  4. Repair and Maintenance: When a motor requires maintenance or repair, accurate winding resistance measurements are crucial for diagnosing issues and ensuring proper motor performance after maintenance tasks.
  5. Motor Design: Engineers use winding resistance values during the motor design process to optimize motor performance and efficiency.

In conclusion, a Motor Winding Resistance Calculator simplifies the assessment of a motor’s winding health and performance. Accurate resistance measurements help maintain motors, prevent breakdowns, and ensure they operate efficiently, reducing downtime and maintenance costs while improving overall productivity.