Electrical Power

hi sir today i have a different question...

i have one source transformer with the capacity of 50KVA, connected with two load 10kw (resistive and inductive load)...


Let suppose transformer p.f is 0.8...


How can i find load in KVA,load power factor...

I answered in the prior submission, it is 10KW / 0.8 = (use your calculator)

but sir 0.8 is our transformer power factor
which is actually depends on the its no laod losses in KVAr and Kw capacity rating


and load has its own kvar rating so it has its own power factor

Don't you mean the measured power factor once a load is connected? I am uncertain of why you ask. Any way the principal is the same the transformer has principally magnetizing inductance (primary + some leakage which we will assume is small). In parallel with that is has resistive losses both copper wire, core losses (several types). Also load losses if connected. An efficient transformed unloaded has a very high low PF

Again KW / KVA = PF, two of these you know => KW = 50KVA * 0.8, which gives you the resistive losses of the fully loaded transformer which is 40KW. This means that you can support 40KW of resistive load.

So again if the spec on the transformer is 50KVA and a PF of 0.8, then this states you can have a max load of 40KW (resistive).

PF = 40KVA / 50KVA = 0.8.

I hope this answers the question. If you need the power factor of the transformer with a 10KW load, not that hard. The reactive power is SQRT( 50^2 - 40^2) = 30KWR

I hope this answers the question. If you need the power factor of the transformer with a 10KW load, not that hard. The reactive power is SQRT[ 50^2 - 40^ ] = 30KWR

I'll use brackets instead of parens.

PF = 10 / (SQRT [ 10^2 = 30^2 ] = 0.32

and

The reactive power is SQRT[ 50^2 - 40^2 ] = 30KWR

sir i want to know about measured power factor of the load and how can we measure the connected load in KVA if i know kw only?
I know these things there must be

Transformer Load

KVA>> Load in KVA

Kw (depends on load) fix load either in resistive or inductive load..

KVAR depends on coil and depends on the inductive load

transformer p.f depends load p.f depends on the inductive load
on no load losses
now we know about transformer KVA rating 50 KVA and power factor 0.8 and Kw sharing capacity 40kw and connected load is 10kw( inductive and resistive load)
now kindly help me how can i check about load details mention above..

sir i want to know about measured power factor of the load and how can we measure the connected load in KVA if i know kw only?
I know these things there must be

1-Transformer KVA written on the name plate and fix.
2-Transformer Kw sharing capacity depends on the load on the transformer.
3-Kvar losses depends on its core and coil losses

-----------------------
1- Load in Kva depends on the load capacity and it is different from the transformer load.
2-Load Kw are fix (resistive and inductive)
3- load kvar depends in the inductive load
4-load power factor mean how much we have total load in kva on the transformer and how much is a active load so it has different power factor not same as with the transformer..
now we know about transformer KVA rating 50 KVA and power factor 0.8 and Kw sharing capacity 40kw and connected load is 10kw( inductive and resistive load)
now kindly help me how can i check about load side details not transformer side...

sir i want to know about measured power factor of the load and how can we measure the connected load in KVA if i know kw only?
I know these things
1-Transformer KVA written on the name plate and fix. lets take 50kva
2-power factor of the transformer let suppose 0.8
3-Transformer Kw sharing capacity which is 40kw.
4-Kvar losses depends on its core and coil losses 30KVAR
———————————-i want to find these details from the load side----------------------------------
1- Load in Kva on the trasformer which is depends on the load(resistive and inductive) and it is different from the transformer KVA rating.
2-Load Kw are fix (resistive and inductive) which i know lets take 20kw
3- Total load kvar which is depends on the inductive load.
4-load power factor mean>>
Load in kw on the transformer/ Load in KVA on the transformer
so it has different power factor not same as for the transformer 0.8
now we know about transformer KVA rating 50 KVA and power factor 0.8 and Kw sharing capacity 40kw and connected load is 10kw( inductive and resistive load)
now kindly help me how can i check about load side details not transformer side…

Ok I actually design/build/model transformers, they aren't 50/60 Hz transformers and aren't using sinusoidal power sources, but doesn't matter. A transformer is a transformer.

You gave me the following:

1) 50KVA rating
2) 0.8 PF (which I assume is at rated DC load otherwise it is completely arbitrary)
3) You gave me 10KW load

If you ask me to design/build this transformer I would need a lot more information. For instance I don't know what the transformers efficiency is so I don't know what the unloaded PF would be (estimate).

The inductance of the transformer won't change as a function of load ( more or less, small percentage), it's effective losses which are essentially in parallel with the load will change, principally because of heat and or perhaps some harmonics showing up in the current wave form.

As to running an inductive load, that's easy because it is just reflected back to the primary and is in parallel with the primary inductance. If that load is a motor then of course depending on the torque the motor is under, the PF reflected to the primary will change. A stalled motor represents large reluctance, small resistance, spun up then the equation is opposite.

So since you haven't really given me enough information. on your application, I am unable to specify the parameters..

FYI, manufactures of 50/60Hz transformers are really bad at specing a transformer. design in Engineering terms.

Sorry can't help.

hi guys
i want to know some thing "Hight voltage Transformers()":http://powertransformers.in/custom_transformers.html
can any one tel me

thanks

what you need to know about it???

You mentioned an inductive load, but you didn't provide that information. The PF given for the transformer is really meant for the purpose of doing power factor correction, which would involve adding capacitance on the line to reduce the reactive power reflected on the mains, which the power utility must pay for in terms of distribution cost.

Also all a transformer is, an impedance reflecting device. What is important is allowable current in the transformer which produces heat. The number I provided 10 40KW of resistance. This current, depending on the voltage doesn't matter if it's inductive or resistive, it still produces heat.

So instead of calling it 40KW, you could call it 40KVA, which could be inductive or resistive, so from this you can now decide the inductance given the resistive load of 10KW.

Inductive load = SQRT [ 40KVA^2 - 10KW^2 ] = 38.73KVAR in terms of an inductance in parallel with your 10KW resistive load. All this is stating is: this is the load that will reflect over into the primary causing current to flow and produce heat in the transformer windings.

Interesting that the secondary inductance will actually increase the PF, but it will not allow you to draw more current through the windings.