Transformer

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Marcio

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Mike how do you calculate this question. If the temperature in oil-filled transformer increases from 18 C to 50 C, the increase in oil volume will be - a.1.44%, b.4%, c.2.56%. and Excessive power transformer noise at the start of operation is most likely caused by: a. An open feeder switch, b. A loose brace, c. An open load fuse. Help I am a student electrician. Thanks Marcio. I like your videos in YouTube. #2- Excessive power-transformer noise at the start of operation is most likely caused by a. An open feeder switch. B. A loose brace. C .an open load fuse. Thanks Marcio
 
Problem #1:
If the temperature in oil-filled transformer increases from 18 C to 50 C, the increase in oil volume will be:

Mineral Oil Thermal Expansion Coefficient: α = 7.5 x 10-4 /°C (Ratio of the relative change of volume to a change in temperature)
Temperature Rise: ΔT = [50°C –18°C] = 32°C
Change in Volume (Expressed in Percentage): [α x ΔT x 100] = 2.4%

A. 1.44%,
B. 4%,
C. 2.56% (closest answer based on approximate α)

Problem #2:
Excessive power-transformer noise at the start of operation is most likely caused by:

A. An open feeder switch, (no effect)
B. A loose brace, (a loose brace can rattle and is more pronounced during energization)
C. an open load fuse (no effect)
 
xptpcrewx said:
Problem #1:
If the temperature in oil-filled transformer increases from 18 C to 50 C, the increase in oil volume will be:

Mineral Oil Thermal Expansion Coefficient: α = 7.5 x 10-4 /°C (Ratio of the relative change of volume to a change in temperature)
Temperature Rise: ΔT = [50°C –18°C] = 32°C
Change in Volume (Expressed in Percentage): [α x ΔT x 100] = 2.4%

A. 1.44%,
B. 4%,
C. 2.56% (closest answer based on approximate α)

Problem #2:
Excessive power-transformer noise at the start of operation is most likely caused by:

A. An open feeder switch, (no effect)
B. A loose brace, (a loose brace can rattle and is more pronounced during energization)
C. an open load fuse (no effect)
Click to expand...
Thanks very much.
 
xptpcrewx said:
Problem #1:
If the temperature in oil-filled transformer increases from 18 C to 50 C, the increase in oil volume will be:

Mineral Oil Thermal Expansion Coefficient: α = 7.5 x 10-4 /°C (Ratio of the relative change of volume to a change in temperature)
Temperature Rise: ΔT = [50°C –18°C] = 32°C
Change in Volume (Expressed in Percentage): [α x ΔT x 100] = 2.4%

A. 1.44%,
B. 4%,
C. 2.56% (closest answer based on approximate α)

Problem #2:
Excessive power-transformer noise at the start of operation is most likely caused by:

A. An open feeder switch, (no effect)
B. A loose brace, (a loose brace can rattle and is more pronounced during energization)
C. an open load fuse (no effect)
Click to expand...
your answer was very good. I asked other people these questions and none of them will be able to answer. i am a student of electricity. Thanks Marcio
 
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