Control of Electric Drives MCQs | Page - 8

Q. 71) The characteristics of drive for crane hoisting and lowering are which off the following?

Q. 72) In ........the speed can be varied by changing the position of brushes

Q. 73) In which of the following applications variable speed operation is preferred?

Q. 74) The number of operations per hour in case of class IV contactor will be around

Q. 75) In case of contactors, the duty in which the main contacts remain closed for a period bearing a definition relation to the no-load periods, is known as

Q. 76) In case of contactors the ratio of the in service period to the entire period, expressed as a percentage is known as

Q. 77) A class I contactor should be mechanically sound to withstand

Q. 78) Which of the following pair is used for frequency converters ?

Q. 79) Belted wound rotor induction motors are preferred for

Q. 80) The cooling time constant is usually