1. What is the temperature of Class B?
a) 120°C
b) 130°C
c) 155°C
d) 180°C
Explanation: 120°C refers to the temperature of Class E. 155°C refers to the temperature of Class F. 180°C refers to the temperature of Class H.
2. Which among the following is the example of Class Y?
a) Varnish
b) Insulation oil
c) Paper
d) Resins
Explanation: Varnish is an example of Class A. Even insulation oil is an example of Class A. Resins is an example of Class E.
3. Which among the following is the example of Class B?
a) Inorganic material with adhesives
b) Hard fiber
c) Wood
d) Impregnated oil
Explanation: Impregnated oil is the example of Class H. Hard Fiber is the example of Class Y and Wood is the example of Class A.
4. Which among the following is an example of Class F?
a) Paper lamination
b) Nitrile rubber
c) Asbestos
d) Silicone
Explanation: Paper lamination is the example of Class E. Nitrile Rubber is the example of Class A. Asbestos is the example of Class B.
5. Silicone rubber is an example of Class H.
a) True
b) False
Explanation: Class H is one of the insulation classes having temperature about 180°C. Silicone rubber is one of the examples of Class H
6. What is the concept of power rating of machines with respect to voltage?
a) the required supply voltage for smooth running of the machine
b) the required supply voltage for stopping the machine
c) the required supply voltage for speeding the machine
d) the required supply voltage for slowing up the machine
Explanation: Power rating is nothing but the standard value at which the machine is said to be safe in operation. Rating determines the voltage which allows the smooth running of the machine.
7. What is the concept of power rating of machines with respect to current?
a) Maximum permissible amount of current that can easily flow
b) Minimum permissible amount of current that can easily flow
c) Maximum permissible amount of current that can stop the machine
d) None of the Above
Explanation: Power rating always deals with two variables, one is current and the other is voltage. When it comes to the current, it is the maximum permitted current that can be allowed into the machine
8. What happens if there is insufficient rating of the machine?
a) The efficiency of the machine increases
b) The efficiency of the machine improves
c) Damage and shutdown occurs
d) Loading problems occur
Explanation: When there is insufficient rating, it can lead to the damage of the windings of the machine. It indirectly, leads to the shutdown of the machine to avoid more hazards.
9. What happens if the power ratings of the machine are decided liberally?
a) Damage occurs to the machine
b) Efficiency of the machine improves
c) Long life of the machine
d) Uneconomical usage of the machine
Explanation: If the power rating becomes very liberal, then it causes a high initial cost. Along with the high initial cost, loss of energy also occurs and leads to uneconomical usage
10. If the power ratings are crossed, machine breakdown occurs.
a) True
b) False
Explanation: Every machine has a permissible limit for both voltage and current, for its efficient operation. If the limit is crossed, it will lead to the breakdown of the machine.