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The term, 'percentage impedance', is a little misleading, as it is defined as 'the value of primary voltage that will cause rated current to flow in the secondary winding, expressed as a percentage of the rated primary voltage'.
So, the test is carried out as follows: the secondary winding is short-circuited through an ammeter capable of reading the rated secondary current. A variable voltage is applied to the primary winding. The primary voltage is gradually increased until the ammeter indicates rated secondary current. That primary voltage is then expressed as a percentage of the rated primary voltage -and that value is the transformer's 'percentage impedance'.
Wiki User
∙ 12y ago
Wiki User
∙ 13y ago10% of 250
imdence of transformer can be determined by taking short ckt test. short HV winding , inject voltage in LV winding gradually till secondary current reaches full load current. The voltage at which full load current is achieved is impedance voltage of transformer. % of the same is % impedance
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∙ 9y agoImpedance is based on the thickness and type of wire used, the number of turns, type of core, etc. To calculate, you have to have all this information.
On large Transformers, short circuit tests are performed to determine the impedance.
Another Answer
I assume you are referring to a transformer's 'percentage impedance'?
The term, 'percentage impedance', is a little misleading, as it is defined as 'the value of primary voltage that will cause rated current to flow in the secondary winding, expressed as a percentage of the rated primary voltage'.
So, the test is carried out as follows: the secondary winding is short-circuited through an ammeter capable of reading the rated secondary current. A variable voltage is applied to the primary winding. The primary voltage is gradually increased until the ammeter indicates rated secondary current. That primary voltage is then expressed as a percentage of the rated primary voltage -and that value is the transformer's 'percentage impedance'.
Wiki User
∙ 9y agoThe simple impedance is measured by running the transformer on load and off load. The on-load voltage is less than the off-load voltage, and the impedance is equal to the change in voltage divided by the load current.
Another Answer
You are probably referring to the transformer's 'percentage impedance', which is one of the characteristics listed on its nameplate data.
Percentage impedance is rather confusing because it is expressed in terms of voltages!
To conduct a test to determine the percentage impedance, the secondary winding is short circuited, and a variable voltage is applied to the primary winding. This voltage is gradually increased until the secondary current reaches its rated value, and that voltage is noted.
The value of the percentage impedance is then the value of primary voltage which causes rated current to flow in the secondary winding, expressed as a percentage of the rated primary voltage.
% impedance =
[(primary voltage causing rated current in secondary) / (rated primary voltage)] x 100%
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How do you calculate the current of the secondary side of the transformer without a load are impedance known?
Without a load the secondary current is zero, by definition.
How do calculate secondary current of step down transformer?
The secondary current is determined by the load. So, divide the secondary voltage by the load impedance.
The purpose of transformer percentage impedance?
Inherently, the actual impedance seen at the secondary voltage will be different than that seen at the primary voltage. To make things easy, we use symmetrical components, where transformers are reduced to a p.u. (per unit) impedance. 100 x p.u. is equivalent to the percentage impedance you are referring to. When converted to per unit, a transformer has one impedance, not two, so it does not matter whether you are looking through the transformer from the secondary or the primary.
What are three requirement for connecting the transformer in paralle?
Transformer capacity (kvA) shall be identical, Both transformer impedance, secondary voltage and frequency shall be identical.
What is percentage impedance?
In electrical engineering, the percentage impedance of a transformer is the voltage drop on a full load, which is expressed as a percentage of the specified rated voltage. It's measured by conducting a short circuit test.
How do you calculate the current of the secondary side of the transformer without a load are impedance known?
Without a load the secondary current is zero, by definition.
How do calculate secondary current of step down transformer?
The secondary current is determined by the load. So, divide the secondary voltage by the load impedance.
How do you convert percent impedance of transformer to impedance value?
The apparent impedance looking into a transformer from one side will not be the same as looking in it from the other, which is why percent impedance is used. If you are looking from the high voltage winding (I'm labeling #1) to the low voltage winding (#2), you must scale the percent impedance as follows: (% impedance) x (Winding #1 nominal voltage)^2 / (transformer base VA)
What are the advantages of Transformer coupling method?
transformer coupling ensures maximum power transfer is obtained even if the output impedance is not equal to the load impedance
The purpose of transformer percentage impedance?
Inherently, the actual impedance seen at the secondary voltage will be different than that seen at the primary voltage. To make things easy, we use symmetrical components, where transformers are reduced to a p.u. (per unit) impedance. 100 x p.u. is equivalent to the percentage impedance you are referring to. When converted to per unit, a transformer has one impedance, not two, so it does not matter whether you are looking through the transformer from the secondary or the primary.
How would you calculate the admittance if you were given impedance?
To calculate the admittance if you are given the impedance, you take the inverse of the impedance ( that is 1/z).
What is the effect of transformer impedance on regulation?
The lower the impedance, the lower the voltage drop across the transformer as it is loaded. This means regulation is better, since voltage variance is smaller.
How a transformer can be used as impedance matching?
If the line impedance is Z0 and the load is ZL then connect the load using a transformer with N turns ration. N=sqrt(Z0/ZL)
What is the effect of low impedance transformer on regulation?
The lower the impedance, the lower the voltage drop across the transformer as it is loaded. This means regulation is better, since voltage variance is smaller.
What is the relationship between frequency and the size of a transformer?
Basically the characteristics of a transformer depends on the impedance(resistance) and on the coupling of its primary and secondary coils. The impedance of a coil depends on the frequency, as the frequency increases you need less volume of iron core and less number of turns in the coil for a given impedance, then reducing the size of the transformer.
What type of transformer configuration will you select to design a high input impedance and low output impedance amplifier?
main volage
What is impedance of transformer?
The transformer impedance is the amount of voltage applied for transformer during the load test.Answer.I really don't agree with the answer given by the previous user.Impedance is the total vector opposition offered by the transformer to the flow of current i.e the vector sum of its pure resistance (R) and it's inductive reactance (XL). http://en.wikipedia.org/wiki/Electrical_impedanceAnother AnswerThe 'impedance' of a transformer is usually expressed as a 'percentage impedance', which is defined (perhaps rather confusingly!) as the ratio of the primary voltage that will result in the full rated current flowing through the secondary, to the rated primary voltage.
