Question { Nokia, 26248 }

What are Drift and Diffusion currents?

Answer

In condensed matter physics and electrochemistry, drift
current is the electric current, or movement of charge
carriers, which is due to the applied electric field, often
stated as the electromotive force over a given distance. It
is distinguished from thermally-induced diffusion current

Question { Siemens, 25521 }

In a 3 phase squirrel cage induction motor why does rotor
rotate?
will 3 phase transformer rotate like a motor if it is
placed on bearings and powered up? give reason

Answer

even we keep a transformer connected in star or delta,it
dont rotate why because there is a specific placement of
armature conductors to exert a torque on it.

simply saying we don't get a superb curry by mixing all the
spieces. we get it only through a specific exercise.

Question { 17506 }

why a pure inductive circuit has zero power output?

Answer

during the inductive circuit it stores energy in the form of
magnetic field which can't be used directly.
we can use the power directly only through heat.which is
resistive load

Question { 8964 }

What do you mean by pf of a generator? Power factor purely
depends on the load (wether inductive, reactive or unity)
then what does the pf mentioned on the generator nameplate
means?

Answer

I try this,



see,power factor is the percentage of resistive load in the
total circuit.as the power factor is one it indicates the
pure resistive which is real in number which can be
converted to the what ever the real energy we want like
rotatory motion etc...

frm:rajeshbeesetty@yahoo.com

Question { 6822 }

what is 2 phase motor?

Answer

simply saying,
2 phase motor is that which consists of two wires input(1
phase and 1 neutral)

Question { GMR, 7289 }

What is hysteresis losses?

Answer

experiment:

take a iron rod which is copper wire is wounded around
it.when the current is passed through it ,it acts like a magnet.
suppose a dc regulated supply is given,
give a supply of 1 amp let it has some 1 henry
increase the supply
to 2 amp let it has some 2 henry
increase the supply
to 3 amp let it has some 3 henry


now decrease the supply
to 2 amp what we think is it should has 2henry but it don't
it decreases slightly to 1.8

This says that when sinusoidal is given to a machine,
positive half consists of 2 equal values in which the
magnetic strength wont be equal.

this leads to some loss..........

Question { 23510 }

what happens to current , when voltage drops .?

Answer

see,
consider a resistive circuit ,
when ever voltage is applied, voltage drops at the resistance.
but current flows.........


consider this example,
you are pushing a big block,this pushing force is voltage.
its movement is current as this known to everyone,
what happened to the force you applied?















it has dropped!!!!!!!!!

from :rajeshbeesettty@yahoo.com

Question { 83044 }

What is Residual Voltage & Residual Current?

Answer

This case arises only in series dc generator
current should be sent around the poles to magnetize.
this current can the source(generator).
current is passed through poles if it is loaded.
but if it is not loaded current is zero through the field.
load voltage should be zero actually.but this dont
happen.we us egenerator frequently.due to this poles are
partially magnetized this causes some voltage appear called
residual voltage.



i haven't heard about residual current

Question { 10352 }

types of motors suitable for escalators with reason

Answer

we use wound type induction motor why because it high
intial torque which is required in this case.

Question { L&T, 8177 }

Explain briefly about current , voltage and power

Answer

talking practically current can be analogally feeled in
other way:
we take a tank which consists of water of some height.
we shall make some hole at the bottom.the bigger the hole
the smaller the resistance.
The definitions are here:
1)the disharge is known as current electrons/sec
2)the force applied on the bottom water is known as the
voltage
3)if you keep some hand at the hole you feel some force
which is power

Question { L&T, 7016 }

define electrical field?

Answer

a field of force surrounding a charged particle

Question { 6858 }

what happens when we give ac supply to the dc motor?and why?

Answer

when an ac is given to a dc machine ,current under north or
south poles change their direction 100 times per second
so ,ideally it should move to and fro motion continously
which may cant work practically

Question { 11692 }

why neutral wire don't shock?

Answer

my doubt is ,
during the positive cycle voltage drops at the load.but
during the negative half cycle current is drawn from
earth.so potntial should appear at the neutral during -ve
half cycles.
then we should feel shock?