# Introduction To Transformers Flashcards

1
Q

Describe induction

A

The process of producing a voltage by the interaction of magnetic fields and a conductor

2
Q

Describe mutual induction

A

When a change of current in one circuit causes a voltage to be induced into another circuit

Also called transformer action

3
Q

What are the 2 types of transformer losses

A

Eddy currents
Hysteresis

4
Q

Describe hysteresis

A
1. Losses due to molecular friction caused by reversal of the direction of current flow
2. Proportional to frequency of source voltage, higher the frequency, greater the loss
3. Can be limited by using silicon steel in construction
5
Q

Describe eddy currents

A
1. Currents that are induced into the metal core material by the changing magnetic field
2. Can be limited by using laminated sheets
6
Q

What are the 3 types of transformers

A
1. Core
2. Shell
3. H-type
7
Q

Which transformer type has the least leakage flux and which has the most

A

Core type has the most
H-type has the least

8
Q

What is the primary winding

A

The winding that is connected to the input voltage

9
Q

What is the secondary winding

A

The winding that is connected to the load

10
Q

Describe percent impedance

A
1. Used for calculating transformer losses, voltage regulation, and system short circuit currents
2. It is found by performing a short circuit test
11
Q

What are three functions of single phase transformers

A
1. Step up the voltage
2. Step down the voltage
3. Isolate one circuit from the other
12
Q

What is the purpose of using taps on transformers

A

To obtain the proper name plate voltage

13
Q

What is the meaning of a tap labeled 5% FCBN

A
1. This tap would be used when the primary supply voltage is 5% lower than the rated transformer primary voltage
2. Because it’s a full capacity tap, KVA will be maintained
14
Q

What is the meaning of a tap labelled 5% FCAN

A
1. The tap would be used when the primary supply voltage is 5% higher than the rated transformer primary voltage
2. Rated KVA capacity is maintained
15
Q

What is the meaning of a tap labelled 2.5% RCBN

A
1. The tap would be used when the primary supply voltage is 2.5% lower than rated transformer primary voltage
2. Because it is a reduced capacity transformer, the rated KVA will also be reduced