why is the rating of transformer done in kva and not in kw.
Answer Posted / kirti
kVA is the unit for apparent power. Apparent power consists
of active and reactive power. Active power is the share of
the apparent power which transmits energy from the source
(generator) to the user. Reactive power is the share of the
apparent power which represents a useless oscillation of
energy from the source to the user and back again.
It occurs when on account of some inertia in the system
there is a phase shift between voltage and current. This
means that the current does not change polarity synchronous
with the voltage. But the heat generated in a winding as
well as the eddy current losses generated in a transformer
core depend on the current only regardless of whether it
aligns with the voltage or not.
Therefore the heat is always proportional to the square of
the current amplitude irrespective of the phase angle (the
shift between voltage and current). So a transformer has to
be rated (and selected) by apparent power.
| Is This Answer Correct ? | 1 Yes | 0 No |
Post New Answer View All Answers
What is the difference between a Root Locus plot and a Bode plot?
where rlc series ckt used?
What is the dependency of stiffness on load angle??
3 phase Motor will be given 2 phase after 2 to 5 second we given 3rd phase so Motor Run sum-time in forward or sum time run reverse direction. All time phase sequence is not change. Why motor run in reverse direction? Please Explain........
what do u understand about FACTS? how they are useful?
Control wiring of a dol starter for forward and backward
Draw the line diagram of diffretial relay connected to transformer?
hi, in the event earth grounding is not available in a project, is there any other way to make the elcb work? fyi, i have an instant water heater (6.5kw) installed, however if there is grounding in the heating element inside the heater assembly, i will get grounded. thank you in advance to those who will answer my question.
What the difference between three phase contactor (coil 110vac) & three phase SSR (control voltage 110Vac)? May I use contactor in place of SSR?
why and how current drawn by battery charger depends upon the altitude where it is located?
EXPLAIN THE WORKING OF SERIES REACTOR IN HT CAPACITOR BANKS (FOR VOLTAGES & CURRENTS)
what are the different kind of cables used for transmissions?
should %impedance be high or low in a power transformer? if so why?
If anyone would like to know or practice for FEWA papers contact me on mohamedrashad2@hotmail.com Just completed the supervisor exam in April 2021
WHY THREE PHESE SYSTEM VOLTAGE APPLIED IN 440 VOLT