(A) High Voltage winding
(B) Low Voltage Winding
(C) None of above
(D) All of above
Ans : (A) High Voltage Winding
Explanation:
- Cylindrical winding using circular conductors are mainly employed for high voltage winding with voltages 6.6, 11 or 33kv for ratings upto 600-1000 kva.
Mcq-2-The Cylindrical winding in Transformer using round conductors are mainly employed for
(A) High Voltage Winding
(B) Low Voltage Winding
(C) None of the Above
(D) Both Windings
Ans: Low Voltage Winding
Explanation:
- The Cylindrical winding using round conductors are mainly employed for low voltage winding up to 6.6 kv for ratings up to 600-750 kva.
Mcq-3 Which winding used for high current in transformer ?
(A) Helical Winding
(B) Cylindrical Winding
(C) Cross Over Winding
(D) Sandwich winding
Ans: (A) Helical Winding
Explanation:
- Helical windings are employed for LV coils of medium and high capacity transformers where the number of turns is small but the current is high (As high as 2000A).
- Low Voltage windings of medium and high capacity transformers, therefore, require the use of a conductor consisting of a row of parallel rectangular conductors arranged in one radial direction of the winding flatwise and close to each other.
Mcq-4 Which winding is employed in power transformers of rating ranging from 150 kva to 300 Mva ?
(A) Cross over winding
(B) Helical Winding
(C) Continuous Disc winding
(D) None of above
Ans: (B) Helical windings
Explanation :
- Helical windings are employed in power transformers of ratting ranging from 150 Kva to 30 Mva at Voltages from 400V to 11kv and sometimes upto 33Kv.
Mcq-5 Every transformer is provided with a .......to indicate hot oil or hottest spot temperature.
(A) Breather
(B) oil gauge
(C) Temperature gauge
(D) Elbow relieff device
Ans: (C) Temperature gauge
Explanation :
- Every Transformer is provided with a Temperature to indicate hot oil or hottest spot temperature.
- It is a self-contained weatherproof unit made with alarm contacts.
- It is of Dial type operated Bordon Gause connected to a thermometer bulb located in the region of hottest oil.
Mcq-6. For absorbing moisture which device is used in the transformer?
(A) Breather
(B) Oil Gauge
(C) Temperature gauge
(D) Bucholz relay
Ans: (A) Breather
Explanation :
- when the transformer becomes hot, the oil expands and due to this process gases are produced and trapped at the top of the transforemer.
- when the transformer oil temperature reduces, the air is absorbed inside the transformer.
- Unless preventive measures are taken, moisture is absorbed during this process, called breathing of transformer.
- Atmospheric moisture are absorbed by the oil and the dielectric properties of oil are reduced.
Mcq-7- The atmospheric air entering the transformer is made moisture-free by passing it through equipment called ...
(A) Bucholz relay
(B) Breather
(C) Pressure relief valve
(D) none of above
Ans: (B) Breather
Explanation:
- The color of silica gel is pink when it is moisture and it becomes blue in colour when it absorbs moisture.
Mcq-8- In core type construction of transformer..
(A) The coils are wound around the two limbs of a rectangular magnetic core
(B) The coils are wound on the central limb of a three limb core
(C) Both of the above
(D) None of above
Ans: (A) The coils are wound around the two limbs of a rectangular magnetic core
Explanation :
- In this construction, each limb carries one half of the primary winding & one half of the secondary winding.
- So as to reduce the leakage reactance to the inside nearer to the core while the HV winding is wound over the lv winding away from the core in order to reduce the amount of insulation material required.