Em Chapter 2

Front 1

Pin=

Back 1

Vp*Ip*cos(theta-p)

Front 2

Pout=

Back 2

Vs*Is*cos(theta-s)

Front 3

Unit transformer does?

Back 3

Generator to transmission level
110 kV+

Front 4

Substation transformer does?

Back 4

Transmission level to distribution level

110 kV+ to 2.3 to 34.5 kV

Front 5

Distribution Transformer does?

Back 5

distribution level to homes level

2.3 to 34.k V to 110/108, 220 V

Front 6

What is transmission line voltage?

Back 6

110kV

Front 7

What is distribution level voltage?

Back 7

2.3 to 34.5kV

Front 8

What voltage is supplied to homes?

Back 8

110,208,220V

Front 9

Vp/Vs=?

Back 9

a

Front 10

Ip/Is=?

Back 10

1/a

Front 11

Apparent power=?

Back 11

Vs*Is=Ip*Vp

Front 12

Real power=?

Back 12

Vs*Is*cos(theta)=Vp*Ip*cos(theta)

Front 13

Reactive power=?

Back 13

Vs*Is*sin(theta)=Vp*Ip*sin(theta)

Front 14

ZL' represents?

Back 14

Load Impedance of primary coil

Front 15

ZL represents?

Back 15

Load impedance of secondary coil

Front 16

Relationship between ZL and ZL'

Back 16

ZL'=a^2*ZL

Front 17

What is e induced for transformer?

Back 17

Front 18

Primary flux consists of what two quantities?

Back 18

Front 19

Secondary flux consists off what two quantities?

Back 19

Front 20

Derive primary flux equation if know that vp(t)=Vm*cos(wt)

Back 20

Front 21

if secondary circuit is open in transformer, a current flows through primary coils. This current consists of?

Back 21

i-m and and i-h+e

(Magnetization current and core loss current)

Front 22

Magnetization current leads or lags the voltage applied (vp(t))

Back 22

Current lags by 90 degress

Front 23

No load current in primary coil of transformer is called?

Back 23

Excitation current

Front 24

Excitation current consists of?

Back 24

Front 25

How to convert real transformer to ideal transformer?

Back 25

1. No hysterisis or eddy current
2. Magnetization curve must be like this
3. Leakage flux must be zero. Meaning all flux induced in primary goes to secondary.
4. Resistance of transformer windings must be equal to zero

Front 26

What are the four losses in a transformer?

Back 26

1. Copper losses (I^2R)
2. Eddy current losses
3. Hysteresis losses
4. Leakage fluxes

Front 27

What are the values of leakage voltages? (Both primary and secondary)

Back 27

Front 28

Magnetization current can be modeled by?

Back 28

Reactance X-M because it lags the voltage by 90 degrees. In inductance, current lags by 90 degrees

Front 29

Eddy current losses can be modeled by?

Back 29

Resistance R-C

Front 30

Show the circuit consisting of losses modeled?

Back 30

Front 31

What is conductance?

Back 31

1/R

Front 32

What is suspectance?

Back 32

1/X (X is impedance of inductive load)

Front 33

What is admittance?

Back 33

1/Z

Front 34

What is admittance of transformer losses?

Back 34

Front 35

How to compute magnitude of transformer admittance?

Back 35

Front 36

How to compute angle of transformer admittance?

Back 36

Front 37

Represent admittance in term of known quantities?

Back 37