PJ High-Frequency DC Test Transformer Wholesale Processing
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I. Product Overview
PJ High-Frequency DC Test Transformer Wholesale ProcessingThe test transformer, also known as a booster, this series of products features small size, light weight, compact structure, complete functions, and ease of use. It is suitable for power, industrial, mining, and scientific research departments to conduct power frequency withstand voltage tests and DC leakage tests on various high-voltage electrical equipment, electrical components, and insulating materials. It is an indispensable instrument in high-voltage testing.
II. Product Structure
The iron core of the YD series light high-voltage test transformer is of single-frame type. The coil adopts a concentric cylindrical multi-layer tower structure, with the primary low-voltage winding wound on the iron core and the secondary high-voltage winding wound outside the low-voltage winding. This coaxial arrangement reduces coupling loss between windings. The product's shell is made into an octagonal structure that fits well with the core, presenting an attractive overall appearance. Transformers above 10KVA are equipped with movable nylon wheels.
III. Working Principle
The YD series light high-voltage test transformer is a single-phase transformer. The working process of a single high-voltage test transformer involves connecting AC 220V (400V for above 10KVA) voltage to the power control box (console). Through the auto-transformer inside the power control box (console), the voltage is adjusted to 0~200V or 0-400V and applied to the primary winding of the test transformer. According to the principle of electromagnetic induction, the required high voltage for testing can be obtained from the high-voltage winding of the test transformer. The working principle diagram is shown in Figure 2.
IV. For DC withstand voltage and leakage tests using the YDJZ AC/DC dual-purpose high-voltage test transformer, the wiring method is shown in Figure 5. Since it is an AC/DC dual-purpose high-voltage test transformer, the high-voltage silicon stack short-circuit rod should be pulled out from the bushing to set the test transformer to DC output state. Before conducting the DC leakage test, first select the resistance value of the current-limiting resistor (water resistor) based on the condition that the output short-circuit current during the leakage test does not exceed the maximum rectification of the high-voltage silicon stack. Then, select the capacitance value of the high-voltage filter capacitor according to the requirements of the DC high-voltage waveform for the test object. To improve the measurement accuracy of the voltage applied to the test object, an FRC resistive-capacitive voltage divider should be connected on the high-voltage side to measure the voltage.
Precautions during DC leakage test operation
(1) Test personnel should divide responsibilities, set a safe distance at the test site, carefully check the grounding of the test object and the test transformer, and assign dedicated personnel to monitor safety and observe the status of the test object.
(2) Before testing the test object, all external connections should be removed, and the object should be fully discharged. The main parts should be cleaned and kept absolutely dry to avoid damaging the test object and causing errors in test values.
(3) For large-capacity test objects (capacitors, ultra-long cables, etc.), the voltage should be raised slowly during the test to prevent the charging current from being too large and burning out the microammeter. If necessary, the voltage should be increased in stages, and the stable readings of the microammeter at each voltage level should be recorded.
(4) During the test, the test object, microammeter, and test device should be closely monitored. Once phenomena such as flashing or breakdown occur, the voltage should be immediately reduced, the power cut off, and the cause investigated.
V. Usage Methods and Precautions
1. Before conducting the power frequency withstand voltage test with the YD high-voltage test transformer, first connect the connecting wires, then connect the power supply. After the power is connected, the red zero-position indicator light will illuminate. Press the start button, and the green indicator light will illuminate, indicating that the test transformer is connected to the control power supply. Press the boost button to start automatic voltage increase until the required rated test voltage is reached. Then press the stop button to stop the high-voltage and low-voltage output, and then cut off the power cord to complete the test.
2. Precautions during power frequency withstand voltage test operation
1) Test personnel should divide responsibilities, set a safe distance at the test site, carefully check the grounding of the test object and the test transformer, and assign dedicated personnel to monitor safety and observe the status of the test object.
2) The main parts of the test object should be cleaned and kept absolutely dry to avoid damaging the test object and causing errors in test values.
3) For tests on large equipment, a no-load test of the test transformer should generally be conducted first, that is, raising the voltage to the test voltage without connecting the test object.
4) During the withstand voltage test, the voltage increase speed should not be too fast, and sudden pressurization should be prevented, such as sudden closing when the voltage regulator is not at zero position. Sudden power-off should also be avoided. Generally, the switch should be opened when the voltage regulator is reduced to zero position.
5) During the voltage increase or withstand voltage test, if any abnormal conditions are found, such as large fluctuations in the voltage and current meter pointers, abnormal sounds from the test object, or signs of insulation burning or smoking, the voltage should be immediately reduced, the power cut off, the test stopped, and the cause investigated.
3. When using this product for high-voltage tests, in addition to being familiar with this manual, national standards and operating procedures must be strictly followed.
Note: The above information and technical parameters are compiled and released by Yangzhou Darui Electric Co., Ltd.
