MCQs of Switch gear and Protective devices (Testing and Commissioning of Electrical Equipments - 2180901)

Testing and Commissioning of Electrical Equipments (2180901) MCQs

MCQs of Switch gear and Protective devices

Showing 21 to 30 out of 59 Questions

21.

The rated voltage is depicted in __________ and used __________ voltage for the three-phase circuit.

(a)	kVrms, phase to phase
(b)	kVrms, phase to Neutral
(c)	kVpeak, phase to phase
(d)	kVpeak, phase to Neutral

22.

____________ of the circuit breaker is the RMS value of the current with which the circuit breaker shall be able to carry at rated frequency and at rated voltage continuously, under specified conditions.

(a)	Rated current
(b)	Short Circuit Current
(c)	Breaking Capacity
(d)	Making Capacity

23.

__________ is the terms expressed the highest number of short-circuit current that the breakers are capable of breaking under specified conditions of transient recovery voltage and power frequency voltage.

(a)	Rated current
(b)	Short Circuit Current
(c)	Breaking Capacity
(d)	Making Capacity

24.

What is the short circuit current rating of CB?

(a)	RMS value of current that a breaker can carry in a fully closed condition without damage, for the specified time interval
(b)	is its ability to withstand the effect of electromagnetic forces of the making current of a circuit breaker.
(c)	the highest number of short-circuit current that the breakers are capable of breaking under specified conditions
(d)	The rated normal current of the circuit breaker is the RMS value of the current with which the circuit breaker shall be able to carry at rated frequency and at rated voltage continuously

25.

The contact resistance of a circuit breaker is. of the order of

(a)	200 ohms ± 10
(b)	20milli ohms ± 10
(c)	20 ohms ± 10
(d)	20 micro ohms ± 10

26.

The insulation resistance of high voltage circuit breaker is

(a)	2000 Mega ohm
(b)	10 k Ohm
(c)	20 Mega ohms
(d)	1k Ohm

27.

In a circuit breaker if the insulation resistance between phase terminal and the earthed frame is less than the specified limit, the probable cause could be

(a)	moisture
(b)	dirty insulation surface
(c)	carbon or copper particles sticking to the internal surface
(d)	any of these

28.

If a circuit breaker does not operate on electrical compound, the probable reason could be

(a)	trip latch defective
(b)	spring defective
(c)	trip circuit open
(d)	any of these

29.

Ionization in a circuit breaker is not facilitated by

(a)	material of contacts
(b)	increase of field strength
(c)	high temperature of surrounding medium
(d)	increase of mean free path

30.

Which circuit breaker is generally used in railway traction ?

(a)	Vacuum circuit breaker
(b)	SF6 gas circuit breaker
(c)	Minimum oil circuit breaker
(d)	Air break circuit breaker

Showing 21 to 30 out of 59 Questions