How to Calculate Motor Capacitor Rated Voltage

The Motor Capacitor Rated Voltage Calculator determines the minimum rated voltage for a capacitor to ensure safe operation. The formula is:

Where:

• \( U_{cap} \): Capacitor rated voltage (Volts).
• \( U \): Supply voltage (Volts).
• 1.42: Safety factor to ensure the capacitor can handle at least 1.42 times the supply voltage.

Enter the supply voltage to calculate the required capacitor rated voltage.

Using the Motor Capacitor Rated Voltage Calculator

This calculator helps select the appropriate capacitor voltage rating for motor applications to ensure safety and reliability.

Input the supply voltage. The calculator outputs the minimum rated voltage, which should be at least 1.42 times the supply voltage.

Example: For a motor rated at 380 V.

1. Supply Voltage: \( 380 \, \text{V} \)
2. Calculation: \( U_{cap} = 380 \times 1.42 = 539.600 \, \text{V} \)
3. Result: Select capacitors with voltage ≥ 450 V (common standard).

Use this tool for safe capacitor selection in motor design.

Common FAQ

Below are frequently asked questions about Motor Capacitor Rated Voltage calculations:

• Q: Why use a 1.42 factor?
  A: It ensures the capacitor can withstand voltage spikes and provide a safety margin.
• Q: What if the result is not a standard voltage?
  A: Choose the next standard voltage rating (e.g., 450 V, 600 V) above the calculated value.
• Q: How accurate is this calculator?
  A: It provides precise results based on the 1.42 safety factor, rounded to 3 decimal places.
• Q: Can negative values be used?
  A: No, supply voltage must be positive; zero or negative inputs leave the result blank.
• Q: Is this for all motor types?
  A: Yes, applicable to single-phase and three-phase motors for capacitor selection.