the principle behind teacformers is electromagnetic 
induction.similarly alternators also work on the same 
principle.

a 3 phase  induction motor also works on the same principle.
a 3 phase Induction motor is a self starting motor with
stator winding and armature winding. these winding behaves
in the same manner as transformer primary and secondary
winding. The armature of an induction motor is short
circuited at the ends to generate current in armature.
Transformers secondary winding current is also zero if it is
left open circuit. Due to these reasons u can say that a 3
phase induction motor can be compared with a transformer
with secondary short circuited..

Alternators and Induction Motors are not static devices 
although they work on same principle as transformer.

CURRENT TRANSFORMER & VOLTAGE TRANSFORMER ARE WORK ON SAME 
PRINCIPAL ( THEY ARE ALSO CALLED INSTRUMENT TRANSFORMER).

The anti-pumping relay allows the breaker to close only 
once for each press of the 'close' pushbutton (or rotation 
of the handle).

the anti pumping device is used to avoid continously 
energising the breaker closing coil once the CB has already 
closed. this is done to avoid burning the coil

This Coil is used to avoid the continuous supply of the 
breaker coil during faulty condition,once we are giving the 
closing pulse during uncleared faults condition the breaker 
will close one time only. After we are giving many more 
closing pulse to the breaker,cannot perform that closing 
operation with the help of anti pumping coil.

ONAN -Oil natural air natural
ONAF-Oil natural air force

The above answer is true.Moreover ,there is a two stage 
forced cooling in some of the transformer 
(ONAN/ONAF1/ONAF2.on First stage forced cooling(ONAF1)  the 
MVA rating increses 33% of the actual rating and on second 
stage cooling(ONAF1) MVA rating increases to 66% of the 
actual rating.

as the oscillators chages the DC input to AC 
output,Oscillators have the ability ot control the input 
signals,that is why Oscillators are used in micro 
controllers

oscillators are used in micro controllers to provide high 
frequency clock signals to the microcontroller.

Oscillators are connected externaly with the 
microcontroller to provides high frequency signal to the 
oscillator circuit in the microcontroller. The oscillator 
circuit provides the clock signal to the microcontroller. 
that's it.

in MC all operations are processed upon trailing or leading 
edges.because MC has several parts.Each parts are 
constructed using Flip-Flop which needs clock for 
triggering.

Your question is wrong . An ac signal can be in any form ie 
sinusoidal or non sinusoidal (square , rectangular , 
sawtooth ).So an ac signal can be represented by any of the 
above mentioned waveform .

Ac signal can be of any form but generally we use 
sinusoidal because we can transform/convert any 
mathematical relation or other equations into sine function 
more easier than any other.
           And also if we observe any machine operation we 
can see the output of stator is a sinusoidal function.So as 
we use more sine funcion rather cosine/anyother function

There are anumber of reasons for this. One of the reasons 
ids that if we take any second order system, the response 
of this system is asinusoid. Secondly, any periodic 
waveform can be written in terms of sinusoidal function 
according to fourier theorem.

power used in da loads are real and that being wasted culd
be termed as reactive.real is da useful one.

reactive power is actually a useful power,which is used for 
boosting up of voltages,it is the stored energy...
(capacitors),injection of reactive power is necessary at 
some cases.

Alternating current
In alternating current circuits, energy storage elements 
such as inductance and capacitance may result in periodic 
reversals of the direction of energy flow. The portion of 
power flow that, averaged over a complete cycle of the AC 
waveform, results in net transfer of energy in one 
direction is known as real power (also referred to as 
active power). That portion of power flow due to stored 
energy, that returns to the source in each cycle, is known 
as reactive power.

 
Power triangle The components of AC powerThe relationship 
between real power, reactive power and apparent power can 
be expressed by representing the quantities as vectors. 
Real power is represented as a horizontal vector and 
reactive power is represented as a vertical vector. The 
apparent power vector is the hypotenuse of a right triangle 
formed by connecting the real and reactive power vectors. 
This representation is often called the power triangle. 
Using the Pythagorean Theorem, the relationship among real, 
reactive and apparent power is:

(apparent power)2 = (real power)2 + (reactive power)2 
Real and reactive powers can also be calculated directly 
from the apparent power, when the current and voltage are 
both sinusoids with a known phase angle between them:

(real power) = (apparent power) * cos(theta) 
(reactive power) = (apparent power) * sin(theta) 
The ratio of real power to apparent power is called power 
factor and is a number always between 0 and 1.

To know the Power Triangle & the above concept here is the
hyperlink for this sub:
http://en.wikipedia.org/wiki/Power_factor#Importance_of_powe
r_factor_in_distribution_systems