1. Connection: Turn off the power switch of the instrument, and connect the wires according to the following method. Single-phase transformer Three-phase transformer Instrument Transformer Instrument Transformer A A A A B X B B C Not connected C C a a a a b x b b c Not connected c c The neutral point of the transformer is not connected to the instrument or the ground. Connect the ground wire of the instrument. Insert one end of the power cord into the power socket on the instrument panel, and connect the other end to the AC 220V power supply. Note: Do not reverse the high and low voltage connections of the transformer! Set connection method Set standard ratio Start data measurement View historical data ↑: Select Confirm: Execute 2. Turn on the power switch of the instrument, and after a moment the main menu will appear on the LCD screen, as shown below. The selected menu is displayed in reverse (black background with white text). At this time, you can press the "↑" key to select the function menu, and press the "Confirm" key to execute the corresponding function. Note: Press and release the key to register one key input. Set connection method Connection: Yy Set standard ratio Start data measurement View historical data ↑: Select Confirm: Save 3. Connection method setting: After entering the connection method setting, the LCD screen displays as follows. At this time, press the "↑" key to select the connection method, and press the "Confirm" key to save the connection method and return to the main menu. Set connection method Set standard ratio Ratio=25.000 Start measurement data View historical data →: Shift ↑↓: Increase/Decrease Confirm: Save 4. Set standard ratio: After entering the standard ratio setting, the LCD screen displays as follows. At this time, press the "→" key to select the data digit, and the selected digit is displayed in reverse. Press the "↑" and "↓" keys to modify the data. After selecting a digit, press the "↑" and "↓" keys to cycle the digit from 0 to 9. If it is the first digit, the digit can only cycle from 1 to 9, and 0 will not appear. After selecting the decimal point, press the "↑" and "↓" keys to move the decimal point cyclically. Set connection method Set standard ratio Adjustment ratio=0.00% Start measurement data View historical data →: Shift ↑↓: Increase/Decrease Confirm: Save If the transformer has taps, the standard ratio set here is the standard ratio of the middle tap. After pressing the "Confirm" key to save the ratio, the LCD screen displays as follows. The setting method for the adjustment ratio is the same as that for the standard ratio. If the transformer has taps, set it according to the actual value; otherwise, set it to 0.00%. After pressing the "Confirm" key to save the adjustment ratio, return to the main menu. 5. After warming up for 5 minutes, select "Start data measurement" and press the "Confirm" key, then the display shows as follows. Connection=Yy? Ratio=25.000? →: No Confirm: Yes ↑↓: Change tap The ratio value displayed on the screen is the actual standard ratio required for this measurement. You can press the "↑" and "↓" keys to modify this value. Each modification step = set standard ratio × adjustment ratio. After the measurement is completed, the display shows as follows. 3rd time Total 3 times Group: 12 o'clock AB: 25.008 0.03% BC: 25.010 0.04% CA: 25.000 0.00% ↑: Page up →: Print Confirm: Return After each measurement, the instrument automatically saves the data, up to 30 data points. When more than 30, the current data is stored in the 30th position, and the first data is cleared, i.e., first in, first out. The left side of the first line shows the position of the current data in the historical data, and the right side shows the number of historical data. The second line is the group. The left side of the third line is the ratio of phase AB, and the right side is the relative error of phase AB, and so on. If measuring a single-phase transformer, only the first three lines are displayed. If the relative error of the measured ratio is greater than 10%, display ">10%"; if the relative error is less than -10%, display "<-10%". Press the "↑" key to view the data. Press the "←" key to enter the print menu, where you can print the current data, print all data, or clear all historical data. Press the Confirm key to return to the main menu.