Electrical Engineering MCQs on Transformer Part 32 – Transformers Multiple Choice Questions
Contents
- 1 The iron losses and full load Cu losses in a 100 kVA transformer are 400 and 1000 W respectively. The efficiency of transformer at full load at 0.85 PF lagging will be
- 2 Transformer oil used in Transformer Provides
- 3 Current transformers are connected in
- 4 The ideal transformer will have maximum efficiency for which condition
- 5 The maximum flux produced in core of transformer is
The iron losses and full load Cu losses in a 100 kVA transformer are 400 and 1000 W respectively. The efficiency of transformer at full load at 0.85 PF lagging will be
The iron losses and full load Cu losses in a 100 kVA transformer are 400 and 1000 W respectively. The efficiency of transformer at full load at 0.85 PF lagging will be:
- 93.88%
- 95.72%
- 98.61%
- 99.03%
Correct answer: 3. 98.37%
Explanation:
Solution:
Full load output = kVA * cos Φ = 100 * 0.85 = 85 kW
Total Full load losses = 400 + 1000 = 1400 W = 1.4 kW
——————————–
Full load input = 85 kW + 1.4 kW = 86.4 kW
——————————-
Full load efficiency = (Full load output/Full load input) * 100
——————————-
Full load efficiency = 85/86.4 * 100
Full load efficiency = 98.37%
Transformer oil used in Transformer Provides
Transformer oil used in Transformer provides:
- Cooling
- Insulation
- Both of these
- None of these
Correct answer: 3. Both of these
Current transformers are connected in
Current transformers are connected in:
- Series
- Parallel
- Any of above
- None of these
Correct answer: 1. Series
The ideal transformer will have maximum efficiency for which condition
The ideal transformer will have maximum efficiency for which condition
- Cannot be determined
- Copper loss < iron loss
- Copper loss = iron loss
- Copper loss > iron loss
Correct answer: 3. Copper loss = iron loss
The maximum flux produced in core of transformer is
The maximum flux produced in core of transformer is:
- Inversely proportional to primary voltage
- Inversely proportional to supply frequency
- Directly proportional to supply frequency
- None of these
Correct answer: 2. Inversely proportional to supply frequency