10KVA/50KV High Voltage Test Transformer
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I. Product Overview
The SSB5KVA/50KV AC high voltage test transformer is a new type of product produced after improvements based on the similar product YDJ (G) high voltage test transformer, in accordance with the national standard for test transformers ZBK41006—89. This series of products features small size, light weight, compact structure, complete functions, and convenient use. It is suitable for power, industrial, mining, scientific research and other departments, for 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.
Type code meaning: No type code indicates AC product, (JZ) - AC/DC dual-use product,
(JC) - AC series excitation product, (JZC) - AC/DC series excitation product.
II. Working Principle
The working principle of the AC/DC dual-use high voltage test transformer is shown in Figure 3. In the figure: the high voltage bushing contains a rectifier silicon stack, connected in series in the high voltage circuit for high voltage rectification to obtain DC high voltage. When a short-circuit rod is used to short-circuit the high voltage silicon stack, AC high voltage can be obtained, and its state is AC output; conversely, when the short-circuit rod is pulled out, its state is DC output.
Figure 3: Schematic diagram of the working principle of a single SSB AC/DC high voltage test transformer
In the test transformer: a, x are the low voltage input terminals; A, X are the high voltage output terminals; E, F are the instrument measurement terminals.
1- High voltage rectifier silicon stack; 2- Silicon stack short-circuit rod.
III. Usage Methods and Precautions
For power frequency withstand voltage tests, connect the working circuit, pull out the short-circuit rod. The X terminal (high voltage tail) of the high voltage winding of the test transformer, the F terminal of the instrument measurement winding, the shell of the test transformer, and the shell of the power control box (console) must be reliably grounded.
Before connecting the power supply, the voltage regulator of the power control box (console) must be adjusted to the zero position (zero position indicator light is on). After connecting the power supply, the red indicator light is on. Press the start button, the green indicator light is on, indicating that the test transformer has been connected to the control power supply and starts to boost voltage.
From the zero position, rotate the voltage regulator handwheel clockwise at a uniform speed to boost the voltage. (Boosting methods include: fast boosting method, i.e., 20S step-by-step boosting method, slow boosting method, i.e., 60S step-by-step boosting method, and extremely slow boosting method for selection) The voltage starts from zero and rises to 75% of the rated test voltage you need at the selected boosting speed, then rises to the required test voltage at a speed of 2% of the rated test voltage per second, while closely observing the indication of the measuring instruments and the condition of the tested object. After the time of applying voltage to the tested object is reached, the voltage regulator should be returned uniformly within a few seconds, and the high voltage should be reduced to below 1/3 of the test voltage. Press the stop button, the high voltage and low voltage outputs stop, then cut off the power cord, and the test is completed.
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