Transformers

Question 1

What is a Transformer?

Answer 1

is a device that converts electrical energy into mechanical energy with a change in voltage but without change in frequency.

Question 2

Core Type

Answer 2

Windings surround the core
2 Limbs
Connected to Low Voltage
Mechanically Weak
Cylindrical
Usage of winding is more due to copper loss

Question 3

Shell Type

Answer 3

core surrounds the windings
3 limbs
H.V
Mechanically strong
Sandwich
Usage of winding is less due to less core and copper loss

Question 4

Pratical Transformer

Question 5

Ideal Transfomer

Answer 5

Infinite permeability
flux leakage is negligible

Question 6

primary and secondary emf induced in primary winding is

Answer 6

v1 = e1=N1 d phase/ dt = omega N1 Phase difference 1 cos omega t
v2= e2 = omega N2 phase 2 cos omega t

Question 7

Rms values of ideal transformers

Answer 7

V1= E1 = root 2 pie N1 phase max
V1=E2=root 2 pie N2 phase max

Question 8

Transformation ratio

Answer 8

V1/ V2= E1/E2= N1=N2 = alpha

Question 9

Max value of flux

Answer 9

phase max = E1/ root 2 pie fN1=E2/root2piefN2= root 2pie =4.44

Question 10

Net exciting current

Answer 10

I1=IO+I’2

Question 11

Voltage Regulation

Answer 11

the leakage reactance is the chief