Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Transformers > Types of cores > Flashcards

Types of cores Flashcards

1
Q

What are the 4 types of cores?

A
  1. EI
  2. Strip
  3. Wound
  4. Toroid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The HV winding is typically the outer winding (True/False)?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Is the LV winding typically the outer or inner winding?

A

Inner

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which of the 4 cores cannot accommodate all voltage ranges?

A

EI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Which of the 4 cores (multiple) can accommodate all voltage ranges?

A
  1. Toroid
  2. Wound
  3. Strip
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which of the 4 cores use a coil that is not placed on the leg of the core?

A

Toroid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

All types of cores are created from a roll of which type of steel?

A

Laminated silicon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How are the windings wound?

A

Concentrically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

The EI core is usually used on which type of transformer?

A

Small, single phase trx up to 5000VA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which core is usually punched out of strip laminations?

A

EI core

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The flux in the bottom yoke of the EI core is cross grain. What are 2 things that result in this?

A

Higher losses
Higher Iex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

For an EI core is a lower or higher grade of steel used? What is the purpose of this?

A

Lower
The lamination is thicker

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What type of insulation is used for an EI core?

A

Varnish

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

As a result of the design choices for insulation and steel, what is the stacking factor of EI cores?

A

0.9 to 0.92

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

When building an EI core using the Butt gap method, how are the E laminations stacked?

A

Stacked up, then uprighted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Where is the coil placed on an EI core?

A

On the center leg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the advantage of the butt gap method for EI cores?

A

Easier to stack

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the disadvantage of the butt gap method for EI cores?

A

Higher Iex and core losses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the disadvantage of interleaving an EI core?

A

More time consuming

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the advantage of interleaving an EI core?

A

The effective gap is reduced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the 3 types of strip core?

A
  1. Butt and Lap
  2. Scrapless Mitre
  3. Full Mitre
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

For an EI core, the coil must be designed to fit the core (True/False)?

A

True

23
Q

For a strip core, the coil must be designed to fit the core (true/False)?

A

False. The core is designed to fit the coil.

24
Q

Strip core laminations come in standard widths (true/false)?

A

True

25
Q

Why must the coil be designed to fit the core for EI?

A

The center lam. determines all the dimensions

26
Q

Why must the core be designed to fit the coil for strip?

A

The strip cores have more flexibility

27
Q

for a butt and lap construction , where must the flux cross the grain?

A

At the corners

28
Q

What is true about core losses, excitation VA, and noise level?

A

They are the highest out of the 3 types of strip core

29
Q

How many gaps are in a butt and lap construction?

A

7

30
Q

How many gaps are in a scrapless mitre construction?

A

8

31
Q

What is true about scrapless mitre construction cross grain flux?

A

It is minimal

32
Q

What is another name for scrapless mitre?

A

Partial mitre

33
Q

What is true about the cross grain flux for full mitre construction?

A

There is no cross grain flux

34
Q

How many gaps are full mitre construction?

A

6

35
Q

Which of the 3 types of strip cores have the lowest losses, Iex, and noise level?

A

Full mitre

36
Q

Which strip constuction has 2 45 degree cuts at the same time?

A

Full mitre

37
Q

A toroid core is used for which type of transformer?

A

CTs

38
Q

Do toroid cores utilize a primary winding?

A

No. A conductor is used as the primary. There is still a secondary

39
Q

A rectangular winding is less space efficient (t/f)

A

False. It is more efficient.

40
Q

A rectangular winding has worse short circuit capability (t/f)

A

True

41
Q

A circular winding takes up less space (t/f)

A

False

42
Q

Due to the circular winding taking up more space, what does that mean for the core in terms of size?

A

The core becomes bigger

43
Q

A circular winding is easier to wind because everything is _______

A

Symmetrical

44
Q

What is the shape of a core for a circular winding?

A

Square

45
Q

What is the shape of a core for a rectangular winding?

A

Rectangular

46
Q

What are the 4 types of windings?

A
  1. Scatter
  2. Layer
  3. Foil
  4. Disc
47
Q

What is the most common winding?

A

Layer

48
Q

What range of current is layer winding used for?

A

Less than 1000A

49
Q

What range of voltage is layer winding used for?

A

Medium voltage ranges

50
Q

Layer winding can be used for inner windings but not outer windings (true/False)?

A

False. It can be used for both

51
Q

Disc winding is used as an outer winding only (t/f)?

A

True

52
Q

Disc winding is used for when voltage is very high (t/f?

A

True

53
Q

What are the 2 types of conductors that foil winding can be?

A

Copper and aluminum

Transformers (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions