how to find apparent power and reactive power?
is it different for static and rotating devices?
sorry but i want to clear my doubt.
if u want to measure it actually then use FLUKE POWER ANALYSERmodel
43B or 435 your job will be done in minutes.
Static or rotating device : this is a mechanical difference (even for AC inductive motors which have electrical rotating magnetic flux)
But the general rule is : as long as there is inductance (or capacitor) inside the load, their is an apparent power and reactive power,
Please note that reactive power is the power responsible of creating the magnetic flux (which is 90% of cases apply on rotating machines :)
To know the apparent and reactive power on any machine, I'll use an inductive motor as an example,
On every motor there is a name plate, which must indicates the apperant power ( Pn in W or KW or HP ) , Voltage ( in V ), and the phase shift ( cos phy ), and nominal current ( In in A)
Those values are for the full load,
for lower loads you should measure the current I and compare it to the nominal current In and devide with the calculated ration I/In=A
P =Pn x A, Q=Qn x A
Now for Q reactive power in VAR
Q=P x tg (Phy)
Phy can be known by any scientefic calculator,
Please note that the Harmonics effects are not considered here.
One mistake at my post
P is the real power in Watt , S is the apperant power in VA
S=Square root (Psqr + Q sqr)
Just replace the word "REAL" instead of "apperant" in my previous post
REAL POWER= VOLTAGE X CURRENT X POWER FACTOR(COS Phi.) – WATTS /KW
APPARANT POWER IS VECTOR SUM OF REAL POWER(KW) AND REACTIVE POWER KVAR(KVAR).
kva= square root ( (kw)square+(kvar) square )
IF YOU KNOW ANY TWO OF THESE (KW,KVA .KVAR OR POWER FACTOR) YOU CAN CALCULATE OTHER PARAMETERS.
Most Users Ever Online: 1178
Currently Browsing this Page:
Spir Georges GHALI: 204
Steven Mill: 88
Ally Kanyondo: 28
Guest Posters: 1356
Newest Members: priyanka kaliwale, selvam, SHIVA KUMAR VANAM, Krishna Kumar bhaskaran, Nijanthan, Vitthal Tatelote
Moderators: Laurent (70), Sudeep (18), Nawaz (12), erickench (38)
Administrators: admin (132)