Precautions for the use of dry-type test transformers

1. The layout of the test equipment should have a sufficient safety distance between the person and the surroundings. Try to avoid arranging equipment and putting high-voltage test leads on the personnel aisles.

1. Before conducting the AC withstand voltage test on site, the shell of the high-voltage dry-type test transformer should be well grounded, otherwise it will endanger the safety of the person and the equipment when the voltage is boosted.

1. Fences should be installed at the test site, and the "Stop! High Voltage Danger" sign should be hung.

2. The test personnel should be familiar with the electrical principle wiring diagram of the high-voltage dry-type test transformer and the test transformer control box. If you need to check the DC leakage current, you can install a rectifier silicon stack and a DC high-voltage microammeter on the high-voltage end of the high-voltage dry-type test transformer. In addition, the DC high-voltage microammeter should be at a high potential. In addition to the shielding box, there should also be an automatic over-current protection device to prevent sudden breakdown and short-circuit or burn-out of the meter during discharge.

3. After the preparations are completed and all the lines are checked correctly, the main power switch can be turned on, and the red switch indicator light can also be lit at this time. If it does not light up, adjust the handle to return to zero counterclockwise, and the red stop button indicator light is on, otherwise the start button does not cooperate.

4. Press the start button and when the green button indicator lights up, the regulator handle rotates evenly and slowly clockwise at a speed of 1.5~2kV per second, and the high voltage gradually rises. Pay close attention to the indication of the voltmeter and the condition of the test product. Until the required test pressure is set.

5. In order to test the withstand voltage test time of the product, the timing time required by the timer can be started, and the timing and alarm switch can be pressed, that is, the product voltage tolerance can be tested within a specified time, and then the alarm will be notified, if If the tested product fails, the overcurrent relay will automatically trip. The voltmeter reading is the value of the breakdown voltage of the product.

6. If you need to protect the tested product from breakdown, you can adjust the discharge voltage of the protective ball to 1.15 times the test voltage by continuously connecting the protective gap on the high-voltage side.

For power frequency withstand voltage test, please pay attention to check whether the capacity of the equipment is sufficient and to avoid resonance.

The working ground wire (high voltage tail, the ground wire at the end of the stabilized capacitor) and the protective ground wire (control box enclosure) should be grounded reliably.

During the test, if there is an input power indicating that the town swings irregularly, check whether there is an impact electrical equipment such as a motor or electric welding. If there is, a pause or other reasons should be found.

The climate (temperature, humidity) requirements of the test work meet the requirements of the test regulations, and shielding measures should be taken when necessary.

During the test, if it is found that the pointer of the voltmeter swings greatly, the indication of the ammeter increases sharply, or the test product has smoke, flashover, abnormal burning smell, etc., immediately stop the test, cut off the power supply, and check the cause.