Why we Specify Transformer rating 433 V Instead of 415V ?

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Why we Specify Transformer rating 433 V Instead of 415V
?

Question Posted / anoop

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Why we Specify Transformer rating 433 V Instead of 415V ?..

Answer / n. ramesh

Power distribution network is supposed to have a voltage
drop of around 4%. As the utility provider has to assure a
three phase voltage of 415 V at consumer's metering point,
the secondary phase to phase voltage of the distribution
transformer is specifed at 4% higher than standard three
phase-phase to voltage of 415 V, which works out to 433 V.

Is This Answer Correct ?

46 Yes

6 No

Why we Specify Transformer rating 433 V Instead of 415V ?..

Answer / n manivannan

Appliances rated voltage is 415V. If Trasformer is specied
at 415V, it will further drop down at receving end and
appliances may not work

To compensate Voltage drop at receiving end

Is This Answer Correct ?

42 Yes

12 No

Why we Specify Transformer rating 433 V Instead of 415V ?..

Answer / ash

433V is the no load voltage. that is when the transformer
is supplied at its HT side but without any load connected
to the LV side.

Is This Answer Correct ?

18 Yes

6 No

Why we Specify Transformer rating 433 V Instead of 415V ?..

Answer / sagar surve

Appliances rated voltage is 415V. If Trasformer is specied
at 415V, it will further drop down at receving end and
appliances may not work

Is This Answer Correct ?

15 Yes

9 No

Why we Specify Transformer rating 433 V Instead of 415V ?..

Answer / gopalen sv

When the transformer is installed near to the LV distribution and no significant voltage drop occurs because of short length of cables then the problem of high voltage like 250 volts in single phase results in many fused bulbs. Motors rated at 400 V will experience 430 plus volts. Before deciding secondary voltage such conditions should be taken into account.

Is This Answer Correct ?

3 Yes

2 No

Why we Specify Transformer rating 433 V Instead of 415V ?..

Answer / andy d

It is to do with the transformer % impedance, As mentioned open circuit LV side of a transformer would measure 433V, Fully loaded the transformer volt drop is equal to the % impedance. A typical 1MVA DY11 transformer would be around 5% impedance at full load, i.e. the secondary voltage reduces voltage to 411V. This is a lower value then 415V however it is not advisable to run transformers at 100% if you want a long life.

Is This Answer Correct ?

1 Yes

1 No

Why we Specify Transformer rating 433 V Instead of 415V ?..

Answer / dheeraj

It is a standard

Is This Answer Correct ?

3 Yes

16 No

Why we Specify Transformer rating 433 V Instead of 415V ?..

Answer / percy

433 IS LILNE TO LINE VALUE OF 250

415 IS NOT DIVISIBLE BY 1.732