Question { 9873 }

Where the excitation is given either stator or rotor in
actually in power plants?

Answer

in alternators, we recieve power from
stator side. Now rotor contains
electromagnet to generate poles...so that
rotating magnating field generated by
rotor cuts stator winding.. Hence emf is
generated on stator winding..
Now elecromagnet needs supply to
become magnet.. So excitation is given to
rotor.

Question { Power Grid, 20543 }

what will happen when power factor is leading in
distribution of power?

Answer

i think when the power factor at
distribution side increases, the recieving
voltage increases according to farranti
effect. But at recieving side we dont
require more than rated voltage. It can
damage the equipment by damaging the
insulation, which is not rated for that
much higher voltage....

Question { 20595 }

whats the one main difference between UPS & inverter ?
And electrical engineering & electronics engineering ?

Answer

ups is used in industries for continuous ac
supply with battery bank. changeover
time is very fast...gives half to 1 hour
backup time to safely shut down of the
equipments.
And inverter is having comparatively more
changeover time..

Question { 6030 }

what is the differenc between A.C. and D.C, which is more
dangerious?

Answer

ac is alternate current.
Dc is direct current.
In our house 230 V ac is used. If u get
shock.. There is a chance to escape as
voltage is low and ac current crosses zero
at every half cycle...
But dc current can do much damage to u
as it does not crosses zero...constant full
dc voltage is applied to u.