Power System MCQs Part 5

Contents

- 1 The symbol for complex power is
- 2 Generally motor devices account for what percentage of power system load
- 3 For limiting current chopping in vacuum circuit breakers, the contact material used has
- 4 Heating and lighting devices account for what percentage of power system load
- 5 I and T are the line current and the torque respectively when DOL starter is used, these quantities when Y/Δ starter is used, are

## The symbol for complex power is

The symbol for complex power is:

- P
- Q
- S
- R

Correct answer: 3. S

## Generally motor devices account for what percentage of power system load

Generally motor devices account for what percentage of power system load

- 10%
- 30%
- 70%
- 99%

Correct answer: 3. 70%

## For limiting current chopping in vacuum circuit breakers, the contact material used has

For limiting current chopping in vacuum circuit breakers, the contact material used has

- Low vapour pressure and high conductivity properties
- Low vapour pressure and low conductivity properties
- High vapour pressure and low conductivity properties
- High vapour pressure and high conductivity properties

Correct answer: 3. High vapour pressure and low conductivity properties

## Heating and lighting devices account for what percentage of power system load

Heating and lighting devices account for what percentage of power system load

- 10%
- 30%
- 70%
- 99%

Correct answer: 2. 30%

## I and T are the line current and the torque respectively when DOL starter is used, these quantities when Y/Δ starter is used, are

I and T are the line current and the torque respectively when DOL starter is used, these quantities when Y/Δ starter is used, are:

- 1/√3, T/ 3
- 1/3, T/ √3
- 1/√2, T/ √2
- 1/2, T/4

Correct answer: 1. 1/√3, T/ 3