1. What is Motor Resistance?

Motor resistance is a fundamental electrical property that measures how much a motor opposes the flow of electric current. It's crucial for understanding motor performance, efficiency, and troubleshooting electrical issues in DC or single-phase motors.

2. How Does the Calculator Work?

The calculator uses Ohm's Law:

Where:

• \( R \) — Resistance in ohms (Ω)
• \( V \) — Voltage in volts (V)
• \( I \) — Current in amperes (A)

Explanation: The resistance is calculated by dividing the voltage across the motor by the current flowing through it.

3. Importance of Resistance Measurement

Details: Measuring motor resistance helps in:

• Diagnosing motor winding conditions
• Identifying short circuits or open windings
• Calculating power consumption
• Determining motor efficiency

4. Using the Calculator

Tips:

• Measure voltage across motor terminals
• Measure current in series with the motor
• For accurate results, motor should be stationary (locked rotor)
• Values must be positive (voltage > 0, current > 0)

5. Frequently Asked Questions (FAQ)

Q1: Why measure motor resistance?
A: Resistance measurement helps identify winding issues, insulation problems, and predicts potential motor failures.

Q2: What's a typical resistance range for motors?
A: Varies greatly by motor size and type. Small motors may have 1-100Ω, while large motors can be in milliohms.

Q3: Should the motor be powered when measuring?
A: No, for safety and accuracy, use a multimeter on unpowered motor. This calculator is for theoretical calculations.

Q4: How does temperature affect resistance?
A: Resistance increases with temperature (positive temperature coefficient). Measurements should account for motor temperature.

Q5: Can I use this for 3-phase motors?
A: This calculates single winding resistance. For 3-phase motors, measure each phase separately and compare values.