Chapter 2 Flashcards

Anatomy

1
Q

Internally, what are the 3 main components that make up a Transformer?

A

The core, the windings and the insulating fluid

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2
Q

What else are Transformers equipped with?

A

Pressure relief valves

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3
Q

What are CSP Transformer equipped with internally?

A

Fuses

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4
Q

What does the core of a transformer provide?

A

A path for magnetic coupling of the two windings

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5
Q

What does the core concentrate?

A

The magnet flux lines, which substantially improves effeciency

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6
Q

What is the core made of?

A

Thin laminations of gran-oriented silicon steel rolled into layers, with each side coated with an insulating material.

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7
Q

What does the core have a significant impact on?

A

The wat losses of the transformer

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8
Q

What are the two configurations of a Transformer’s Core?

A
  • Wound Type Core

- Shell Type Core

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9
Q

What does the core type for distribution transformers depend upon?

A

Manufacturer and the type of transformer

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10
Q

What is the type of steel that’s been recently utilized?

A

Amorphous Steel

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11
Q

Why is Amorphous Steel utilized?

A

To further reduce the losses within the core

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12
Q

What is the most popular material for the windings?

A

Copper

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13
Q

Why is Copper the most popular used material?

A

Low resistance and superb conductivity

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14
Q

Which typically has smaller sized wire used for the windings the primary or secondary windings?

A

Primary Windings

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15
Q

What shape might the winding wire take?

A

Either round or in rectangular ribbon form

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16
Q

What are the winding conductors coated with?

A

Insulation to to prevent the turns from shorting out

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17
Q

Where are the ends of the windings attached?

A

To the primary and secondary terminals

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18
Q

What are the secondary winding ends tagged with?

19
Q

Where are the ends of the windings brought out from when attaching them to the primary and secondary terminals?

A

Brought out of the core and coil assembly

20
Q

What is the role of the Insulating fluid?

A

Cooling and insulating the core and coil assembly

21
Q

How does it facilitate the cooling process?

A

By transferring the heat generated in the coil and core assembly to the tank or radiators, where it will be dissipated to the outside atmosphere

22
Q

What happens as the core heats?

A

The oil rises.

23
Q

What happens when the oil rises?

A

It’s forced against the case of the transformer where it radiates heat into the atmosphere and cools.

24
Q

What happens when the oil cools?

A

It circulates down to the bottom of the core.

25
What is convection?
The circulation of the oil by heat
26
What is the insulating fluid?
Mineral oil
27
What is important to understand about Mineral oil?
It's flammable under certain conditions
28
What does PCB stand for?
Polychlorinated Biphenyls
29
What is askarel?
The term PCB relates to a substance that can be a part of an insulating fluid.
30
What has PCB been determined as?
To be harmful to the environment and is prohibited in new transformers.
31
What is important to know when working on older transformers?
Be alert to the type of insulating fluid
32
What is the insulated fluid indicated by?
A non-PCB stag or sticker, or by the data on the nameplate
33
What can build up inside a transformer?
Pressure in the form of gas can build up inside
34
Why would pressure build up inside?
Short in the windings, which breaks down the impurities in the oil creating gas
35
What can this pressure do?
Build up and blow off the lid
36
What do manufacturer's now include to alleviate this potential?
A valve located just above the oil level, which allows internal pressure to escape to the atmosphere
37
What does the valve do?
The valve will vent when the internal pressure reaches approx. 10lbs/sq inch.
38
What is normally added when older transformers are built?
Pressure Relief Valve
39
What do the internal fuses in CSP Transformers do?
Isolate and protect the transformer from internal faults.
40
What must be done to replace this fuse?
The transformer must be de-energized and the lid removed
41
What else does a CSP Transformer have?
An Internal Secondary Breaker
42
What does the internal secondary breaker do?
Disconnect the hot legs in the event of an overload or a short circuit on the secondary side
43
Where are the Pad-Mounted Transformers fuses?
Internal, but operated externally, located in the primary compartment and are under the oil level