Question

Voltage of three phase motor is generally kept at

• A. 110 V
• B. 220 V
• C. 415 V
• D. 660 V

Hint:

Recall the relationship between three-phase line-to-line voltage (\(V_L\)) and phase voltage (\(V_{ph}\)):
\(V_L = \sqrt{3} \times V_{ph} = \sqrt{3} \times 240\text{ V} \approx 415\text{ V}\).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Power systems use standardized voltage levels to transmit and distribute electric power.
Standard low voltage levels vary depending on whether the system is single-phase or three-phase.

Step 3: Detailed Explanation:
In standard commercial and industrial AC systems in India and many other regions:
1. The standard single-phase phase-to-neutral nominal voltage is approximately \(230\text{ V}\).
2. The standard three-phase line-to-line nominal voltage is approximately \(415\text{ V}\) (sometimes historically referred to as \(400\text{ V}\) or \(440\text{ V}\)).
Three-phase motors are industrial loads and are generally rated for and run on this standard three-phase level of \(415\text{ V}\).

Step 4: Final Answer:
The correct option is 3, which corresponds to 415 V.