Free Printable Transformer

1.

For 2kVA 100/1000 V transformer, High voltage full rated current is

a)

20 A

b)

2 A

c)

200 A

d)

Can not be evaluated

2.

For a transformer copper losses are also known as

a)

variable loss

b)

iron loss

c)

eddy current loss

d)

losses in shunt parameter

3.

For a transformer, core losses are not equivalent to

a)

iron loss

b)

sum of eddy current losses and hysteresis losses

c)

losses in series parameters

d)

losses in shunt parameters

4.

In transformer which quantity do not remain same after transformer action at another winding end.

a)

magnetizing flux

b)

current

c)

kVA

d)

frequency

5.

Which one is true

a)

$MMF=FLUX\times RELUCTANCE$

b)

$FLUX=MMF\times RELUCTANCE$

c)

$RELUCTANCE=MMF\times FLUX$

d)

$MMF=FLUX\times NUMBER\ OF\ TURNS\$

6.

Which one is true for E1 and E2 (if N1= N2)

a)

Both are equal in magnitude as well as phase angle.

b)

Both are neither equal in magnitude nor in phase angle.

c)

Both are equal in magnitude but 90 degree apart to each other in phase angle.

d)

Both are equal in magnitude but 180 degree apart to each other in phase angle.

7.

Which one is not the condition for ideal transformer.

a)

Resistance of primary and secondary winding must be zero

b)

Leakage flux must be zero.

c)

Permeability must be zero.

d)

Eddy current and Hysteresis losses must be zero.

8.

For a 50 kVA 5000/500 V , 50 Hz single phase transformer, copper losses in HV side at 5 A is 1000 W. The copper loss at full load would be

a)

1000 W

b)

2000 W

c)

4000 W

d)

250 W

9.

For a 10 kVA single phase transformer, at what load efficiency would be maximum if iron loss and full rated copper losses are 200 W and 800 W respectively.

a)

5 kVA

b)

10 kVA

c)

8 kVA

d)

7.5 kVA

10.

Which one is not correct for auto transformer

a)

It has better voltage regulation in resistance and reactance of the single winding is less

b)

It has lower efficiency than two winding transformer.

c)

Used only for slight variation of the output voltage from input voltage

d)

It is also used as a voltage regulator

11.

Eddy current is the current which flows

a)

at the surface of magnetic core

b)

at the surface of primary and secondary copper winding

c)

due to change in orientation of

magnetic dipoles

d)

due to leakage of flux in air

12.

Which quantity in the magnetic field is analogous to the current in the electric field

a)

permeance

b)

reluctance

c)

flux

d)

mmf

13.

The sum of Hysteresis and Eddy current losses are also called

a)

Ohmic loss

b)

Heat loss

c)

Copper loss

d)

Constant loss

14.

Which one is true for single phase transformer,

a)

b)

c)

d)

None of these

15.

Which one is incorrect,

a)

b)

c)

d)

16.

The relative permeability of the ferromagnetic material is

a)

More than one

b)

More than 10

c)

More than 100

d)

Less than one

17.

If the area of hysteresis loop of a material is large, the hysteresis loss in this material will be

a)

Small

b)

Zero

c)

None of the these

d)

Large

18.

The transformer ratings are usually expressed in terms of

a)

Volts

b)

Amperes

c)

kW

d)

kVA

19.

The main advantage of auto transformer over a two winding transformer is

a)

Hysteresis losses are reduced

b)

Saving in winding material

c)

Copper losses are negligible

d)

Eddy losses are totally eliminated

20.

The efficiency of a transformer is maximum when

a)

It runs at half full load

b)

it runs at full load

c)

its Cu loss equal iron loss

d)

it runs over load

Transformer

Total questions: 20

Worksheet time: 40mins

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