File Name: single phase transformer regulation and efficiency .zip
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This is the supply voltage V 1 magnetizing current I 0, supply current I 1, R e q, j X e q is the referred load current I 2 dash, and this is the referred load voltage V 2 dash. While this equivalent circuit is important for finding out different performance parameters from a user point of view certain performance parameters are very important. For example, one of the most important performance parameter is the efficiency of transformer. Now efficiency as in the case of any other power processing equipment for a transformer the efficiency is defined as the symbol is nu is defined as output power divided by the input power.
The open circuit and short circuit test are performed for determining the parameter of the transformer like their efficiency, voltage regulation, circuit constant etc. These tests are performed without the actual loading and because of this reason the very less power is required for the test.
The open circuit and the short circuit test gives a very accurate result as compared to the full load test. The purpose of the open-circuit test is to determine the no-load current and losses of the transformer because of which their no-load parameters are determined.
This test is performed on the primary winding of the transformer. The wattmeter, ammeter and the voltage are connected to their primary winding. The nominal rated voltage is supplied to their primary winding with the help of the ac source. The secondary winding of the transformer is kept open, and the voltmeter is connected to their terminal. This voltmeter measures the secondary induced voltage. As the secondary of the transformer is open, thus no-load current flows through the primary winding.
The value of no-load current is very small as compared to the full rated current. The copper loss occurs only on the primary winding of the transformer because the secondary winding is open. The reading of the wattmeter only represents the core and iron losses. The core loss of the transformer is the same for all types of loads. Working component I w is. Putting the value of W 0 from the equation 1 in equation 2 you will get the value of the working component as.
Magnetizing component is. Equivalent exciting resistance is. Equivalent exciting reactance is. The phasor diagram of the transformer at no load or when an open circuit test is performed is shown below. The iron losses measured by the open circuit test is used for calculating the efficiency of the transformer. The short circuit test is performed for determining the below mention parameter of the transformer. The short circuit test is performed on the secondary or high voltage winding of the transformer.
The measuring instrument like wattmeter, voltmeter and ammeter are connected to the high voltage winding of the transformer. Their primary winding is short-circuited by the help of thick strip or ammeter which is connected to its terminal. The low voltage source is connected across the secondary winding because of which the full load current flows from both the secondary and the primary winding of the transformer. The full load current is measured by the ammeter connected across their secondary winding.
The flux is set up in the core of the transformer. The magnitude of the flux is small as compared to the normal flux. The iron loss of the transformer depends on the flux. It is less occur in the short circuit test because of the low value of flux. The reading of the wattmeter only determines the copper loss occurred, in their windings.
The voltmeter measures the voltage applied to their high voltage winding. The secondary current induces in the transformer because of the applied voltage. Then the full load copper loss of the transformer is given by. Equivalent resistance referred to the secondary side is. From the phasor diagram. Equivalent impedance referred to the secondary side is given by. The equivalent reactance referred to the secondary side is given by.
The voltage regulation of the transformer can be determined at any load and power factor after knowing the values of Z es and R es. In the short circuit test the wattmeter record, the total losses, including core loss but the value of core loss are very small as compared to copper loss so the core loss can be neglected. Thanks for explaining the process of open circuit and short circuit test. Can you add some mathematical example here? I need to do some math about open circuit and short circuit test.
Thanks for well-explained details related to short cct and open cct tests on transformer. It was very helpful. Your email address will not be published. Save my name, email, and website in this browser for the next time I comment. Skip to content The open circuit and short circuit test are performed for determining the parameter of the transformer like their efficiency, voltage regulation, circuit constant etc.
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Recieve free updates Via Email! Home Electrical machines Power system Ask a question Contact electricaleasy. Share: Facebook Twitter Linkedin. Sumpner's test or back to back test on transformer is another method for determining transformer efficiency , voltage regulation and heating under loaded conditions. Short circuit and open circuit tests on transformer can give us parameters of equivalent circuit of transformer , but they can not help us in finding the heating information.
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The term voltage regulation identifies the characteristic of the voltage change in the transformer with loading. The numerical difference between no-load and full-load voltage is called inherent voltage regulation. We can say that voltage regulation is an important measure for the performance of the transformer.
Переложив берет-ту в левую руку, правой он взялся за перила.
За спиной у него послышался какой-то звук. Он замер, чувствуя мощный прилив адреналина. Неужели Стратмор каким-то образом проскользнул наверх. Разум говорил ему, что Стратмор должен быть не наверху, а внизу. Однако звук повторился, на этот раз громче. Явный звук шагов на верхней площадке.
The open circuit and short circuit test are performed for determining the parameter of the transformer like their efficiency, voltage regulation, circuit constant etc.