The measurement accuracy of the transformer is high, the measurement wiring is complicated, and the fundamental frequency measurement of the power frequency is added. The environmental interference is very large. Therefore, each device is often qualified in the measurement bureau, and the data after the combination is more significant. All the air valves we can supply as well, such like VA air valves,AJV air valves,CUMSA standard VA air valves,VA air valves with sieves,Z491 air valves,APV air valves for moulds. Not only with the perfect quality but also most favorable prices. We trust that we can make win-win cooperation.Weclome to send a inquiry to us. Air Valve,Air Release Valve,Air Relief Valve,Air Check Valve,Air Vent Valve Changsha Borun Mould Co. Ltd. , http://www.borunmouldparts.com
The accuracy of the transformer calibrator is not an important indicator of the instrument. In the transformer calibration procedure, the test error caused by the entire loop must not exceed 20% of the transformer level to be tested. In fact, the calibrator is required. The data displayed in actual work must be authentic and authentic.
1. Selective frequency filter performance of transformer calibrator:
Transformer test is the measurement of the fundamental wave. Due to the error of the secondary current of the standard and the transformer under test, the second and third-order distortion of the current waveform is very large (up to 500%) and modulated by high-frequency interference. Therefore, the calibrator Must have good frequency-selective filtering performance, separate the fundamental wave, and make measurements.
The factors of distortion are very complex. In low-accuracy (less than 0.5 class) transformer tests without saturation core compensation, the general distortion is about 10%, and the effect is not obvious. The national standard requires the calibrator harmonic attenuation to be more than 32dB, enough Satisfy use. However, this indicator is too low when testing high-precision or transformers with a saturated core.
The domestic test of the project does not measure, and the general manufacturers often do not give indicators. When users purchase new instruments, they should compare with 2700, HGE2 or HE15 old instruments to determine whether they are credible.
2. The introduction load of the calibrator and the matching with the standard transformer:
The additional load that the calibrator brings to the transformer under test, and the load that the calibrator brings to the standard transformer, are strictly stipulated in the national regulations. The domestic measurement verification does not detect these indicators, and most manufacturers do not give the indicators. However, they are one of the main reasons for the differences in the verification data of different organizations.
3, wire load:
When the load Z is manufactured, 0.06 ohms resistance is reserved for the connecting wire (individually has 0.05 ohms), so the sum of the three wire resistances A, B, and C in the figure is required to be 0.06 ohms. When the current transformer of the rated load (10VA) is small, the resistance of the wire has a great influence on the data.
4, voltage transformer load leads to the wrong point
The load line and the calibrator voltage sampling line should be led out from the transformer terminals respectively. If one wire is shared, the test error will be introduced due to the voltage drop on the wire.
5, wiring is not standardized error:
With the development of testing technology, the instrument manufacturer has developed a new standard transformer. The new standard has many advantages. For example, a two-stage current transformer can overcome the problem of load matching between standard transformers and calibrators. The use of the unit is still connected in the fifties, but there has been a greater error.
6, ground line:
Because of the frequency measurement, space electromagnetic field and floating potential, it has a great influence on the measurement. In the test, the ground wire plays an important role. The ground wire must be properly grounded according to the regulations. It is still important that the test be performed in a level of 0.05 or higher, or in a high pressure.
It is recommended that when purchasing equipment, users should select a complete set of equipment factories with many years of industry-based, rather than a single-piece production plant, both of which have essential differences in the theory and experience of transformer testing. The correct choice, the first can ensure that all indicators of the instrument are attached to the requirements of the regulations, the second variety of wiring, instrument matching are designed and designed by the manufacturer, can avoid the use of errors, affect product quality.
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