, Voltage ratio test equipment: the DLBB transformer turns ratio tester
Transformer no-load case, the high voltage winding voltage and low voltage winding voltage is called the
voltage ratio.
The purpose of the transformer ratio is check the winding turns are correct, check the tap situation,
whether the layer between the metal short-circuit check the windings, etc., provide the basis for the
transformers ability to put into operation or parallel operation, field measurement of voltage than the
voltage measurement France and the bridge method.
Objective: To measure the ratio and the correctness of ① Check the transformer turns ratio;
② Check the tap condition;
③ transformer failure, commonly used measurement voltage than check the transformer if
there interturn short circuit;
④ judge transformer parallel operation.
When two parallel running of the transformer secondary no-load voltage difference of 1% of the rated
voltage, the two transformers in the circulation will reach about 10% of the rated current, thus increasing
the losses of the transformer, taking the capacity of the transformer voltage than the difference should be
limited within a certain range according to relevant regulations, the voltage less than three transformers,
the allowable tolerance of ± 1% ± 0.5% of all other transformer. Measuring the voltage ratio method,
generally have a dual voltage meter and variable than the bridge method.
Second, the groups of test equipment: the DLBB transformer group tester
Transformer connection group is a very important technical parameters of the transformer, transformer
parallel operation groups of the same, otherwise it will cause the voltage differential transformer in
between, the formation of circulation, so the transformer should be put into operation Connection Group test.
Wiring group of test methods: DC law, dual voltage meter, ratio bridge method, the phase-meter method.
Measurement of transformer polarity: DC law, exchange law.
Phase Meter measurement should pay attention to matters: (1) single-phase transformer supply single-phase
power supply of three-phase transformer three-phase power;
② provisions in the table of the test transformer high voltage side of the
supply phase voltage;
③ When wiring, pay attention to the polarity of the phase two coils;
④ if necessary, before the test, with the correctness of the known
transformers to check the phase of the terminal group table.
Transformer load test equipment: DLBT transformer capacity, and empty load tester
Transformer no-load test is applied from the transformer on either side of the rated voltage of the sine
wave rated frequency, the other winding open trial of measurement of transformer no-load loss and no-load
current. Rated voltage is applied (usually low-voltage side) under the experimental conditions, on one side of
the test product, the remaining side open, the test voltage is the rated voltage of the low pressure side of
the low test voltage and test current of a few percent of the rated current or thousands points when the site
easy to measure the load test is generally applied voltage from the low voltage side, running at ground
potential line-side and shell should be properly grounded. No-load current shall be taken as the average of
the three-phase current, and conversion as a percentage of the rated current. Power transformers in the
replacement of the winding to conduct the load test, measuring the load current and no-load loss at rated
voltage, and its purpose is to check the existence of inter-turn short-circuit fault, check the core
lamination insulation condition, as well as through the core screw rod and the connecting piece of insulation,
when the fault occurs, the no-load loss and no-load current will increase.
Measuring no-load loss should pay attention to the problem: ① current, voltage accuracy of not less than
0.5;
② The low power factor wattmeter;
③ maximize the use of dual-Watt meter to measure;
(4) should be noted that the polarity of the transformer;
⑤ Note remanence impact.
Impedance test equipment: DLZK transformer circuit impedance tester
Impedance test, also known as short-circuit test, which is a measurement of the rated current of the load
loss and impedance voltage, also known as load test, the main winding to check whether the deformation or the
existence of interturn short circuit impedance test is generally applied voltage from the high pressure side,
short-circuit low-voltage side. In this way, the test current for the high-voltage rated current, small test
current, easy to meet the requirements, the measurement of the impedance voltage of the high pressure side of
a large value, the more accurate.
