Tap Changing Transformers MCQs : This section focuses on the "Tap Changing Transformers" in Transformers. These Multiple Choice Questions (MCQs) should be practiced to improve the Transformers skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.
___________ change of voltage is affected by changing the numbers of turns of the transformer provided with taps.
A. Turn-changing Transformers
B. Voltage-changing Transformers
C. Tap-changing Transformers
D. Open-changing Transformers
Explanation: Tap-changing Transformers : The change of voltage is affected by changing the numbers of turns of the transformer provided with taps
How many types of tap-changing transformers?
Explanation: There are two types of tap-changing transformers : Off-load tap changing transformer and On-load tap changing transformer
In which type, the transformer is disconnected from the main supply when the tap setting is to be changed?
A. Off-load tap changing transformer
B. On-load tap changing transformer
C. closed-load tap changing transformer
D. open-load tap changing transformer
Explanation: Off-load tap-changing transformer : In this method, the transformer is disconnected from the main supply when the tap setting is to be changed.
In Off-load tap-changing transformer, The tap setting is usually done automatically.
C. Can be true or false
D. Can not say
Explanation: The tap setting is usually done manually.
While tapping, Which essential conditions need to be fulfilled?
A. The load circuit should not be broken to avoid arcing and prevent the damage of contacts
B. No parts of the windings should be short–circuited while adjusting the tap
C. Both A and B
D. None of the above
Explanation: While tapping, two essential conditions are to be fulfilled : The load circuit should not be broken to avoid arcing and prevent the damage of contacts and No parts of the windings should be short–circuited while adjusting the tap.
Common range pf tap changing is __________
Explanation: Adjustment is normally carried out by off-circuit tap changing, the common range being 5% in 2.5% steps. Daily and short-time control or adjustment is carried out by means of on-load tap changing gear, which makes this application easier.
Negative tapping means ________________
A. less turns than positive tap
B. less turns than principal tap
C. less turns than zero tap
D. more turns than principal tap
Explanation: The principal tapping is one to which the rating of the winding is related. A positive tapping means more turns and a negative tapping implies less turns than those of the principal tap. Tap changing may be achieved by three conditions
With the introduction of on-load tap changers, operating efficiency ___________
A. stays constant
B. depends on the application
Explanation: On-load tap changers are used to change the turn ratio of transformer to regulate system voltage while the transformer is delivering load. With the introduction of on-load tap changer, the operating efficiency of electrical system gets considerably improved
During the tap change, only half of the reactance which limits the current is connected in the circuit.
C. Can be true or false
D. Can not say
Explanation: True, During the tap change, only half of the reactance which limits the current is connected in the circuit.
Which of the following is/are part/s of tap changing circuit?
A. Automatic voltage regulator
B. A time delay relay
C. AVR, time delay relay, compounding elements
D. Compounding elements
Explanation: The main components are an automatic voltage regulator, a time delay relay, and compounding elements. The time delay here, prevents unwanted initiation of a tap change by a small transient voltage fluctuation. It may be set for a delay upto 1 min.