1.
What is the largest rating of alternator manufactured in India?
Correct Answer
A. 500kw
Explanation
The largest rating of alternator manufactured in India is 500kw.
2.
The burden of current transformers is measured in..
Correct Answer
B. Volt Amperes
Explanation
The burden of current transformers is measured in Volt Amperes. This is because the burden of a current transformer refers to the amount of power that can be safely consumed by the connected burden resistor or load. Volt Amperes is a unit that represents the apparent power, which is the product of voltage and current. Therefore, measuring the burden in Volt Amperes indicates the maximum power that the current transformer can handle without causing any issues.
3.
What is the speed of 2 pole alternator at 50Hz frequency?
Correct Answer
B. 3000
Explanation
The speed of a 2 pole alternator is directly proportional to the frequency of the power supply. Since the frequency given in the question is 50Hz, the correct answer would be 3000 RPM (Revolutions Per Minute).
4.
Corona effect will be minimum at
Correct Answer
D. 10 Hz Frequency
Explanation
The corona effect refers to the phenomenon where the surrounding air around a high voltage conductor ionizes, causing energy losses and potential damage. At lower frequencies, such as 10 Hz, the corona effect is minimized because the ionization process requires a higher frequency to occur. Therefore, at 10 Hz frequency, the corona effect will be minimum compared to higher frequencies like 50 Hz, 40 Hz, and 30 Hz.
5.
The line current will be equal to phase current in_____
Correct Answer
Delta
Explanation
In a Delta connection, the line current is equal to the phase current. This is because in a Delta connection, each load is connected between two phases, and the current flows through both phases. Therefore, the total current in the line is the sum of the currents in the two phases, which is equal to the phase current.
6.
The line Voltage will be equal to phase Voltage in_____
Correct Answer
Star
Explanation
In a star connection, the line voltage is equal to the phase voltage. In a star connection, three phases are connected to a common neutral point, forming a star shape. The line voltage is the voltage between any two of the three phases, while the phase voltage is the voltage between any one of the phases and the neutral point. Since the neutral point is common to all three phases in a star connection, the line voltage and phase voltage are equal.
7.
Which material have maximum conductivity?
Correct Answer
A. Silver
Explanation
Silver has the highest conductivity among the given materials. This is because silver has a high number of free electrons that are able to move easily through the material, allowing for efficient flow of electric current. This property makes silver a popular choice for electrical wiring, circuitry, and other applications where high conductivity is required. Gold also has good conductivity, but it is not as high as silver. Aluminum and graphite have lower conductivity compared to silver, while steel has even lower conductivity.
8.
Material of brushes in motor?
Correct Answer
C. Both
Explanation
The material of brushes in a motor can be either copper or graphite. Copper brushes are commonly used in motors as they have good conductivity and can withstand high temperatures. On the other hand, graphite brushes are preferred for applications where low friction and less wear are important. Therefore, both copper and graphite are suitable materials for motor brushes depending on the specific requirements of the motor.
9.
Current transformer is used in the circuit :
Correct Answer
C. Both
Explanation
A current transformer is used in the circuit for both measurement and protection purposes. In terms of measurement, it is used to step down high current levels to a safe and measurable range for instruments to accurately measure the current flowing through a circuit. On the other hand, in terms of protection, a current transformer is used to detect and monitor high currents that could potentially damage the circuit or equipment. It provides a signal to protective devices, such as relays, to quickly disconnect the circuit and prevent further damage.