when i try using your method for the open circuit test method on other numericals in the book i get different answers compared to the ones in the book , forexample this question A single-phase two-winding transformer is rated 20 kVA, 480/120 volts, and 60 Hz. During a short-circuit test, where rated current at rated frequency is applied to the 480-volt winding (denoted winding 1), with the 120-volt winding (winding 2) shorted, the following readings are obtained: V1 = 35 volts, P1 = 300 W. During an open-circuit test, where rated voltage is applied to winding 2, with winding 1 open, the following readings are obtained: I2 =12 A, P2 5=200 W. does the open circuit test have when it works and when it doesnt ? I mean the method you just showed in this video
I think, you should have obtained correct results for the short circuit test (used to find the impedance of the series branch) and somewhat different results for the open circuit test (used to find the admittance of the excitation branch). The reason for different answer is that the open circuit test in the mentioned problem is performed on the secondary side (low voltage side) of the transformer. In that case, to obtain correct answer, multiply the obtained answer with square of the turns ratio. Why? The answer of this why lies in the equivalent circuit of the transformer referred to the secondary side.
Thank you very much for these videos. I was wondering why can the short circuit have its current just be determined with S/V,primary when the open circuit is simply measured? Would the short circuit current always be equal to the power rating divided by the primary voltage?
While performing the short circuit test, we do not apply the rated voltage on the primary side. Then how much voltage is applied? The voltage applied is equal to the voltage that will cause the rated current to flow through the primary side. What is the rated primary current? It is obtained by S/Vp.
There is no easy way to separately find the series impedances of primary and secondary side of the transformer. Furthermore, for most of analysis on circuits with transformers, separate determination of these impedances is not required.
@@MAFarooqi yes Simscape/ Electrical/ Specialized Power Systems/ Fundamental Blocks/ Elements / Three-Phase Transformer ( Two Windings) . Im using matlab 2020a. This transformer block require winding 1 & 2 parameters separately. I’m simulating a delta-star transformer of my working place. It has only short cct and open cct test data only
@@udayanthaniraj you may use the impedances determined using the short circuit test at the primary side of the simscape block, for example, and zero impedance at the secondary side the block.
While performing the short circuit test, we apply a voltage to the transformer such that rated current flows in the transformer. The numerical value of 489V in this particular problem is provided in the problem statement and would have been experimentally obtained after performing the short circuit test on the transformer.
Sir, i can't explain just how wonderful of a lecturer you are. Thank you🙏
Thanks and welcome
when i try using your method for the open circuit test method on other numericals in the book i get different answers compared to the ones in the book ,
forexample this question A single-phase two-winding transformer is rated 20 kVA, 480/120 volts, and 60 Hz. During a short-circuit test, where rated current at rated frequency is applied to the 480-volt winding (denoted winding 1), with the 120-volt winding (winding 2) shorted, the following readings are obtained: V1 = 35 volts, P1 = 300 W. During an open-circuit test, where rated voltage is applied to winding 2, with winding 1 open, the following readings are obtained: I2 =12 A, P2 5=200 W.
does the open circuit test have when it works and when it doesnt ? I mean the method you just showed in this video
I think, you should have obtained correct results for the short circuit test (used to find the impedance of the series branch) and somewhat different results for the open circuit test (used to find the admittance of the excitation branch).
The reason for different answer is that the open circuit test in the mentioned problem is performed on the secondary side (low voltage side) of the transformer. In that case, to obtain correct answer, multiply the obtained answer with square of the turns ratio. Why? The answer of this why lies in the equivalent circuit of the transformer referred to the secondary side.
Thank you very much for these videos. I was wondering why can the short circuit have its current just be determined with S/V,primary when the open circuit is simply measured? Would the short circuit current always be equal to the power rating divided by the primary voltage?
While performing the short circuit test, we do not apply the rated voltage on the primary side. Then how much voltage is applied? The voltage applied is equal to the voltage that will cause the rated current to flow through the primary side. What is the rated primary current? It is obtained by S/Vp.
@@MAFarooqi I see, and is this voltage that is applied the same as the measured short circuit voltage?
@@ynnad7778 Yes.
@@MAFarooqi Thank you very much for the clarification!
Sir, where did you get the open circuit current and power open circuit?
Current and power are measured by the ammeter and power meter, respectively.
I want to know if the data used for the calculation are per-phase data
How to determine primary and secondary side impedances separately?
There is no easy way to separately find the series impedances of primary and secondary side of the transformer.
Furthermore, for most of analysis on circuits with transformers, separate determination of these impedances is not required.
@@MAFarooqi thank you very much for the reply. But in Matlab simulation’s transformer models these impedances are required separately for both sides
Are you using simscape? Which block you are using for the transformer? Delta-Delta?
@@MAFarooqi yes Simscape/ Electrical/ Specialized Power Systems/ Fundamental Blocks/ Elements / Three-Phase Transformer ( Two Windings) . Im using matlab 2020a. This transformer block require winding 1 & 2 parameters separately. I’m simulating a delta-star transformer of my working place. It has only short cct and open cct test data only
@@udayanthaniraj you may use the impedances determined using the short circuit test at the primary side of the simscape block, for example, and zero impedance at the secondary side the block.
Where did you get Vsc= 489V?
While performing the short circuit test, we apply a voltage to the transformer such that rated current flows in the transformer. The numerical value of 489V in this particular problem is provided in the problem statement and would have been experimentally obtained after performing the short circuit test on the transformer.