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101.

What is stacking factor?(a) the allowance made for the power loss(b) the allowance made for the space loss between laminations(c) the allowance made for the heat loss between laminations(d) the allowance made for the power loss between laminationsI have been asked this question in a national level competition.This intriguing question comes from Design of Core and Winding in portion Design of Transformers of Design of Electrical Machines

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Right answer is (b) the allowance MADE for the space loss between laminations

Best explanation: The net CROSS SECTIONAL area is obtained from the dimensions of various PACKETS and an allowance is made for the space LOST between laminations. This allowance is called stacking factor.
Discussion
102.

The area of the window depends on the window space factor.(a) true(b) falseThis question was addressed to me in an international level competition.My question is taken from Window Space Factor in chapter Design of Transformers of Design of Electrical Machines

Answer» RIGHT CHOICE is (a) true

Easy explanation: AREA of the window = Total CONDUCTOR area/window space factor.

The area of the window is indirectly PROPORTIONAL to the window space factor.
Discussion
103.

What is the formula of window space factor, when the transformer rating is 20 kVA?(a) 10 / (30+kV)(b) 12 / (30+kV)(c) 8 / (30+kV)(d) 19 / (30+kV)This question was addressed to me in a job interview.The question is from Window Space Factor in chapter Design of Transformers of Design of Electrical Machines

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Correct answer is (c) 8 / (30+kV)

To EXPLAIN I would say: 10 / (30+kV) DENOTES the empirical value of window space FACTOR for rating between 50-200 kilo-volt-amp. 12 / (30+kV) is the window space factor for transformers having rating around 1000 kVA.
Discussion
104.

What is the formula for the window space factor, when the output is 1000 kVA?(a) 12 / (30+kV)(b) 10 / (30+kV)(c) 9 / (30+kV)(d) 11 / (30+kV)This question was posed to me in examination.Enquiry is from Window Space Factor in division Design of Transformers of Design of Electrical Machines

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Correct option is (a) 12 / (30+kV)

BEST explanation: 10 / (30+kV) denotes the empirical value of window SPACE factor for RATING between 50-200 kilo-volt-amp. When the output is near 1000 kilo-volt-amp then the formula used is 12/(30+kV).
Discussion
105.

What is the relationship of the space factor value with the large and small outputs?(a) small value for both large and small outputs(b) large values for both large and small outputs(c) large value for small output and small value for large outputs(d) small value for small output and large value for large outputsThe question was posed to me in my homework.Question is taken from Window Space Factor in chapter Design of Transformers of Design of Electrical Machines

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Correct choice is (d) small value for small output and LARGE value for large outputs

Explanation: The SPACE FACTOR is directly PROPORTIONAL to the output. If large output is obtained, space factor is HIGH and vice versa.
Discussion
106.

What is the ratings of the transformers for using the empirical value of window space factor?(a) 50-100 kVA(b) 50-150 kVA(c) 50-200 kVA(d) 100-200 kVAThe question was asked during an internship interview.My question is from Window Space Factor in section Design of Transformers of Design of Electrical Machines

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Right choice is (c) 50-200 kVA

Easy explanation: The empirical FORMULA of the WINDOW space factor is used for the transformers of the rating 50-200 kVA. If the transformer rating is HIGHER than 200 kVA then the empirical formula isn’t used.
Discussion
107.

What is the empirical value of window space factor, given the output is 1000kV?(a) 0.09(b) 0.9(c) 0.009(d) 0.0009This question was posed to me during an interview for a job.I'd like to ask this question from Window Space Factor topic in section Design of Transformers of Design of Electrical Machines

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The correct answer is (c) 0.009

The explanation is: EMPIRICAL value of window space FACTOR = 10 / (30+kV)

kV = 1000 kV, empirical value = 10/1030 = 0.009.
Discussion
108.

What is the empirical formula for calculating the value of window space factor?(a) window space factor = 10 / (30+kV)(b) window space factor = 5 * (30+kV)(c) window space factor = 10 * (30+kV)(d) window space factor = 5 / (30+kV)This question was posed to me in quiz.I'd like to ask this question from Window Space Factor in portion Design of Transformers of Design of Electrical Machines

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The correct ANSWER is (a) WINDOW space factor = 10 / (30+kV)

Easiest explanation: The output voltage in kV is calculated first. Then the value is SUBSTITUTED in the FORMULA to OBTAIN the empirical value of the window space factor.
Discussion
109.

What does the insulation and copper of the transformer depend on?(a) current rating(b) voltage rating(c) output power(d) voltage rating and output powerI had been asked this question in a job interview.My question is from Window Space Factor in portion Design of Transformers of Design of Electrical Machines

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The correct choice is (d) VOLTAGE rating and output power

For explanation I would say: The insulation and COPPER of the transformer depend on the voltage rating of the transformer. It also DEPENDS on the output power PRODUCED by the transformer.
Discussion
110.

What does the window space factor depend on?(a) it depends on the core(b) it depends on the armature(c) it depends on the insulation(d) it depends on the insulation and copperThe question was asked during an online interview.I would like to ask this question from Window Space Factor in chapter Design of Transformers of Design of Electrical Machines

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Right choice is (d) it depends on the insulation and copper

For EXPLANATION I would say: WINDOW space factor totally depends on the insulation of the machine. It also depends on the copper WINDINGS PROVIDED.
Discussion
111.

What is window space factor?(a) window space factor = copper area in the window – total window area(b) window space factor = copper area in the window + total window area(c) window space factor = copper area in the window * total window area(d) window space factor = copper area in the window / total window areaI had been asked this question in final exam.Question is taken from Window Space Factor topic in section Design of Transformers of Design of Electrical Machines

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Right choice is (d) window space factor = copper area in the window / total window area

For EXPLANATION: Window space factor is the RATIO of the copper area in the window to the total window area. It is a CONSTANT used in the output equation of transformers.
Discussion