Interview Questions Answers in Electrical Engineering

cameron hunter

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How does frequency affect KVA rating of a transformer? If a 500 kva, 500 to 250 v, 60 hz t/f normally used in Canada is to be operated in Europe on 50 hz frequency then how will its KVA rating change? a-increase b-decrease c-remains same

1 Electrical Engineering 1799

How does frequency affect KVA rating of a transformer? If a 500 kva, 500 to 250 v, 60 hz t/f used in Canada is to be operated on 50 hz in Europe frequency then how will its KVA rating change? a-increase b-decrease c-remains same

1 Electrical Engineering 1868

Answers / { cameron hunter }

Question { 33136 }

How does frequency affect KVA rating of a transformer?
If a 500 kva, 400 v, 60 hz t/f is to be operated on 50 hz
frequency then how will its KVA rating change?
a-increase
b-decrease
c-remains same
Also explain why do u think like that.

Answer

The transformer EMF equation shows that the EMF induced in the secondary or the primary side of a transformer is directly proportional to the product of the flux (Φm) through the transformer core and the frequency. This leads to the flux is proportional to E/f.
For example, the kVA rating of the 500v to 250v 60 Hz transformer will be smaller when used in Europe with a frequency of 50Hz. 500/60 = E/50, E is smaller than 500v on primary side. 250/60 = E/50, E is smaller than 250v on secondary side.

Is This Answer Correct ?

10 Yes

2 No

Question { 1799 }

How does frequency affect KVA rating of a transformer?
If a 500 kva, 500 to 250 v, 60 hz t/f normally used in Canada is to be operated in Europe on 50 hz
frequency then how will its KVA rating change?
a-increase
b-decrease
c-remains same

Answer

The transformer EMF equation shows that the EMF induced in the secondary or the primary side of a transformer is directly proportional to the product of the flux (Φm) through the transformer core and the frequency. This leads to the flux is proportional to E/f.
For example, the kVA rating of the 500v to 250v 60 Hz transformer will be smaller when used in Europe with a frequency of 50Hz.
500/60 = E/50 E is smaller than 500v on primary side.
250/60 = E/50, E is smaller than 250v on secondary side.

Is This Answer Correct ?

0 Yes

0 No

Question { 1868 }

How does frequency affect KVA rating of a transformer?
If a 500 kva, 500 to 250 v, 60 hz t/f used in Canada is to be operated on 50 hz in Europe
frequency then how will its KVA rating change?
a-increase
b-decrease
c-remains same

Answer

The transformer EMF equation shows that the EMF induced in the secondary or the primary side of a transformer is directly proportional to the product of the flux (Φm) through the transformer core and the frequency. This leads to the flux is proportional to E/f.
For example, the kVA rating of the 500v to 250v 60 Hz transformer will be smaller when used in Europe with a frequency of 50Hz.
500/60 = E/50 E is smaller than 500v on primary side.
250/60 = E/50, E is smaller than 250v on secondary side

Is This Answer Correct ?

1 Yes

0 No