Sumpners test is conducted on transformers to determine a temperature b stray losses. To make this resistance test for insulation breakdown. This test can also be used to determine the efficiency of a transformer. Single phase transformer and applications of single phase. The maximum temperature rise in a large transformer is determined by the full load test. Sumpners test or back to back test requires two transformers. A voltmeter, wattmeter, and an ammeter are connected in hv side of the transformer as shown. A1 by load test,open circuit and short circuit test and sumpners test. These two transformer tests are performed to find the parameters of equivalent circuit of transformer and losses of the transformer. To conduct sumpners test on two identical singlephase transformers and to determine its efficiency and regulation characteristics. Theory of operation of singlephase transformers custom. This test reproduces conditions of continuous rated load and the temperature rise occurring during the load. Mod01 lec05 lecture05testing of single phase transformers. The fullload test of large transformers is not possible because considerable wastage of energy occurs and it is difficult to get a suitable load for absorbing fullload power.
Single phase transformer single phase dimmer stat ammeter ac. The advantage of conducting this test is very economical of power, even when the transformers are tested at full load conditions. Otherwise, with incorrect polarity, it is not possible to connect them in parallel. A low voltage of around 510% is applied to that hv side with the help of a variac i. To determine the efficiency and regulation of a given single phase transformer by conducting the oc and sc test and also to draw its equivalent circuit. Singlephase transformers transformer symbols n p number of turns in the primary n s number of turns in the secondary e p voltage of the primary e s. Technologies have developed, and reading sumpner test on single phase transformer manual printable 2019 books can be far easier and much easier.
Test systems equipped with optional high voltage taps will allow testing of transformers with higher. Sumpners test is also called as back to back test on transformers because of connections are in parallel at input side and connections are in series. If the two transformers are connected in parallel, then the polarity should be known for the proper connection of the transformer. Sumpners test back to back test the sumpners test is another method of determining efficiency, regualtion and heating under load conditions. Backtoback test sumpner s test on transformer definition. Singlephase transformer cores 2leg core 3leg core 4leg core fig. Electrical diagram of a sumpners test for singlephase transformers 1 by s. Sumpner test or back to back test on transformer my tech. Depends on the voltage rating of the transformer, but typically a megger is used to test primary to secondary, and each winding to ground. In conducting the sumpner test of transformer the primaries of the two transformers are connected in parallel across the rated voltage supply v 1, while the two secondaries are connected in single phase transformer as shown in fig.
Sumpner or backtobacktest efficiency of a transformer. Open circuit and short circuit tests on single phase transformer. Sumpners test in singlephase transformer mcqs with answers q1. The threephase system application means using three single phase units connected in the threephase system. The connection diagram for the short circuit test on the transformer is shown in the figure below. Concept of coupled circuits, dot convention, writing network equilibrium equations in coupled circuits problems on coupled circuits excluded, principle of transformer action for voltage transformation, constructional details of shell type and core type singlephase and threephase transformers, description of the following types of transformers power transformer. Sumpners test back to back test on single phase transformer. To perform open circuit and short circuit test on a single phase transformer and to predetermine the efficiency, regulation and equivalent circuit of the transformer. What is backtoback test sumpners test on transformer. Info ebook and manual reference sumpner test on single phase transformer manual printable 2019 best ebook you must read is sumpner test. Load test on singlephase transformer and three phase transformers. Load test of a transformer is basically carried out for determining the maximum temperature rise of the transformer. Sumpners test in singlephase transformer mcqs with answers. Polarity testing of transformers is vital before connecting them in parallel.
The size of transformers which can be tested will vary with impedance. Polarity test of a singlephase transformer electrical. Sumpners test or back to back test on transformer is another method for determining transformer efficiency, voltage regulation and heating under loaded conditions. How to do an insulation test of a single phase transformer. Transformer questions and answers electrical academia. To determine regulation and efficiency of a single phase transformer by open circuit o. Short circuit and open circuit tests on transformer can give us. Sumpners test is used to put large transformer on full load. This test is called, backtoback test, regenerative test or sumpners test. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Open circuit test and short circuit test on transformer are very economical and convenient because they are performed without actually loading of the transformer. The full load test on a small transformer is very convenient, but on the large transformer, it is very difficult. Open circuit and short circuit test on transformer.
A 60kva single phase transformer with a primary voltage of 2,400 volts and a secondary voltage of 240 volts. Other results for sumpner s test viva questions and answers. Sumpners test is the test which is used to determine the steady temperature rise if the transformer was fully loaded continuously. Sumpner test or back to back test on transformer this test is conducted instantaneously on two similar transformers and so the transformers temperature rise, efficiency and voltage regulations. Both the tests let us know about the core losses and copper losses in single phase transformer, then why is sumpners test preferred over open circuit and short circuit test. For conducting heat run test on the three phase transformer, full rated. While performing sumpner s test on transformer, if the secondarys are not in series opposition then the meter will read a. Sumpner test of transformer sumpner test on single phase. Experiments for first year electrical engg lab 201415. Load test or back to back test or sumpner s test of. Sumpners test give more accurate results of regulation. For lowvoltage applications, the standard is to test at 500 or v, though there are higher voltage meg. Sumpners test on similar transformers and determination of combined and individual transformer efficiency.
The advantages of three singlephase units are transportation, maintenance, and spare unit availability. The full load test on a small transformer is very convenient, but on the. Sumpners test on a pair of single phase transformers free download as pdf file. Sumpners test back to back test your electrical home. However is not viable to conduct this test by connecting the secondary of the transformer to rated load. The sumpners test requires two identical transformers.
Electrical machines for mechatronics laboratory 2 8 shortcircuit test introduction in the short circuit test, the secondary terminals of the transformer are shortcircuited, and the primary terminals are connected to fairly. Here, two identical transformers are connected back. This test is called, backtoback test, regenerative test or sumpner s test. Testing of single phase transformers oc test sc test sumpner s test or back to back test. This is a more expensive solution, and it is used in the high voltage power system. One transformer is loaded on the other and both are connected to supply. What are the advantages of sumpners test over conventional. Sumpners test provides data for finding the regulation, efficiency and heating under load conditions and is employed only when two similar transformers are available. Here, two identical transformers are connected back to back, such that their primaries are in parallel across the same voltage source and. Sumpner s test of single phase transformer is a very exclusive and important product designed for students of electrical engineering to explain the basic concepts of sumpner s test. While performing sumpners test on transformer, if the secondarys are not in series opposition then the meter will read a. Which of the following statements regarding an idel singlephase transformer having a turn ratio of 1. Why is a megger preferred to an ohmmeter when measuring the insulation breakdown of a distribution transformer. Efficiency of a transformer single phase transformer basic.
Sumpners test electrical engineering interview questions. After observations, the variac is brought to zero position and switch off the. Theory of operation of singlephase transformers definition of transformer an electrical power transformer is a static device, which transforms electrical energy from one circuit to another without any direct electrical connection. Polarity test of transformer polarity means the direction of the induced voltages in the primary and the secondary winding of the transformer. Polarity test and sumpners test on single phase transformers. The sumpner test is carried out on two identical transformers to compute the efficiency of each transformer. Transformers multiple choice questions and answers mcqs electrical engineering interview transformers viva lab manual pdf free download. 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. With this trainer, students can learn about the significance of conduction of. Theory heat run test is one of the type tests on power transformer.
This ppt covers the operating principle,its construction,equivalent circuit and efficiency of a single phase transformer. Load test or back to back test or sumpners test of transformer. Sumpners test or backtoback test on transformer electricaleasy. Sumpners test transformers questions and answers sanfoundry. This test gives the value of total loss accurately as it occurs when it is in actual use. Open circuit or no load test on transformer open circuit test or no load test on a transformer is. Sumpners test give more accurate results of regulation and efficiency than o. This test gives the value of total loss accurately. Sumpner s test back to back test on single phase transformer.
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