actually first of all we calculate the load and after that
we would be able to slect the transformer. ok any how if
you have 1500kva transformer you can take 1200kw to 1350 kw.
its depends upon the dversity factor. how much you will
take.i know only this answer if anybody else has some other
please correct me.
From the given transformer ,the max. power we can take
depend on the load p.f which we connect with the
tranaformer.As the pf has max value of 1,so at unity pf we
can take 1500 Kw from this transformer or the max power
from the transformer we can take is 1500 Kw
Even if you make your power factor unity (which may sometime
disturb your source), you can not load transformer up to
100% of its capacity. It will raise threat to your costly
machines. Being good engineer, you should not let your
consumer exceed loading your transformer more than 90 % that
becomes 1350 kW (if p.f. is unity) and 1100kw (if p.f. is 0.8).
In distribution system, generally the p.f. taken in account
is 0.8. So the maximum kw load available is 1500x0.8=1200kw.
For safest condition the diversity factor should be taken
into account is 80%. So the maximum 960kw (80% of 1200kw) of
load is allowed on a 1500KVA transformer.
In transformer, the current in line with voltage,so here
there is no cosine angle between the voltage and
current.but Practically some angle present in the voltage
and current.so the power factor should be more than 0.9.
KVA = 1500
P.F = 0.9
KW = 1500*09
=1350KW.
For Safe working allowable = 80% of rated of rated voltage.
Safest power = 1350*0.8
= 1080 KW
Dear its very simple
first just convert this 1500 KVA into KW at assumin PF 0.8
which equal to 1200 KW then Calculate the Ampere by the
Below Formula
P = 1.73 X V x I X PF
then you will get the Ampere,and then you can easily find
out the load by ammeter or any how you know abt 1200KW.
so you can put the load 1200 KW but being good engineer
dont put 100 % load on your transformer ,its better if you
put 80 or 90 % load.
thanks
regds
sayed asef s ali
It is interesting how much wrong answers can be gained with
one simple question. I assume that all people answered are
somehow involved with above mentioned theme. To avoid
problems and cost for you in future IŽll give you few hints.
First of all I want to remaind to everybody that
transformers are normally custom made equipment and to
answer this all transformer data has to be presented. Same
well you can ask how far can you drive with the car having
150kW engine!!!
1. I presume that such big transformer feeding not much
equipmnt stating its elektrical KW. On your engine
nameplate you find mechanical kW on engine axe. It has
nothing to do with engine electrical kW.
2. Transformer load is always calculated in Amps. And that
is information what you can always find on all and every
el.equipment as well as on the nameplate of your
transformer. Simple as that.
3. In normal cases you can not presume how many Amps you
will use as it is depending on the load on your equipment
what is varying in real life quite much. So you or use max
Amps stated on nameplates or expected Amps by your
specialists or you set up the Ampmeter and measure it.
4. Normally you dont want to load your transformer
permanently more than 75% as there are always swiching
processes giving load jumps upto few times more than the
full load of your transformer
5. It is very important to consider permanen distortion
level what your equipment emissing back to transformer and
the distortion level coming from higher voltage side. This
is complicated issue what is quite simple to measure, but
for that you really need specialist.
6. Distortion creators in your network are lighting,
smartequipment, variable speed drives, office technology,
UPS systems etc. If you dont have special converter type
transformer then you have to degrade the allowable load as
much you have the distorting equipment. If you have all the
load distorting for example then you dont want to load your
transformer more than half power only. To be honest then
even less, but its again depending on the type of
distortion.
7. Easiest and cheapest is always to ask specialist giving
you stright and exact answers. Trust me - it always pays
back. In this forum you have had answers from the level of
housewife to secondary school students. They are partly
right but non of them giving you really full answer.
In distribution system, generally the p.f. taken in account
is 0.8
Beacuse our transformer is 1500KVA.
SO = 0.8
FROM FORMULA:- KW = KVA*P.F.
so KW = 1500*0.8
KW = 1200
So our transformer upto 100% load= 1200KW
Beacuse we take maximum 80% load on Transformer for safety
so: =1200* 80/100
=960kw
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