1、 Preface
According to IEC and relevant national standards, transformer ratio test is a necessary item in the production, user handover, and maintenance testing of power transformers. This can effectively supervise the quality of transformer products during factory delivery and use, prevent inter turn short circuits, open circuits, connection errors, internal faults or contact faults of voltage regulating switches. The fully automatic transformation ratio tester developed and produced by our company is completely based on the user's on-site usage requirements, with the characteristics of easy operation, complete functions, and stable and reliable data. Can adapt to the needs of variable ratio testing for various large, medium, and small transformers.

2、 Precautions
1. Please read this user manual carefully before use.
2. This instrument can be used both indoors and outdoors, but should be avoided from places such as rain, corrosive gases, excessive dust, high temperatures, and direct sunlight.
3. When wiring, be careful not to connect the high voltage side and low voltage side leads in reverse.
4. After the instrument is turned on, the test leads cannot be short circuited or grounded to each other. Unused lead clamps must be suspended in the air.
5. Attention should be paid to the wiring of the instrument, and the yellow, green, and red colors should correspond to the A, B, C, and three-phase terminals of the transformer, respectively, and should not be connected incorrectly.
6. The maintenance and adjustment of instruments should be carried out by professionals.

3、 Performance characteristics
1. Chinese menu prompts, simple and convenient operation.
2. The variable ratio measurement range is large: 0.9-2200.
3. Powerful function: It can perform single-phase measurement and automatic testing of three-phase windings. Polarity can be measured for both single-phase and three-phase, and the connection group can be freely selected. It can complete the measurement of AB, BC, CA three-phase transformation ratio, error, tap position, tap value and other parameters at once, and can automatically identify the group.
4. Fast measurement speed.
5. Convenient to carry and suitable for field operations.

4、 Technical indicators
1. Variable ratio measurement range: 0.9-2200.
2. Accuracy: ± (0.1% ± 3 words).
3. Resolution: Minimum resolution of 10-3
4. Power supply: 220V ± 10%, 50Hz.
5. Group selection: Y, △, Z-type transformers can be selected.
6. Working temperature: 0-40 ℃.
7. Environmental humidity: less than 80% without condensation.
8. Dimensions: 440 × 260 × 200

5、 Working principle
The schematic diagram of the whole machine is shown in Figure 1

Figure 1 Principle Block Diagram