About withstand voltage tester has developed rapidly in recent years

The withstand voltage tester is also called the electrical end strength tester or the dielectric strength tester. It is also called the dielectric breakdown device, the end strength tester, the high voltage tester, the high voltage breakdown device, and the withstand voltage tester. A test for applying a specified AC or DC high voltage between the live part and the non-live part (generally the shell) of an electrical appliance to check the voltage resistance of the material of the electrical appliance. In long-term work, electrical appliances must not only withstand the rated working voltage, but also withstand the short-term overvoltage that is higher than the rated working voltage during the operation (the overvoltage may be several times higher than the rated working voltage) . Under the action of these voltages, the internal structure of the electrical marginal material will change. When the overvoltage intensity reaches a certain value, the material will be completely broken down, the electrical appliance will not operate normally, and the operator may get an electric shock, endangering personal safety.

Structure and composition of withstand voltage tester:

(1) Boosting part

The voltage regulating transformer, the step-up transformer and the step-up part of the power supply are connected and cut off.

The 220V voltage is connected to the voltage regulating transformer by turning on and cutting off the switch. The output of the regulating transformer is connected to the boosting transformer. Users only need to adjust the voltage regulator to control the output voltage of the step-up transformer.

(2) Control part

Current sampling, time circuit and alarm circuit. When the control part receives the start signal, the withstand voltage tester immediately turns on the boost part power supply. When the current of the circuit under test exceeds the set value and an audible and visual alarm is issued, the power of the booster circuit is immediately cut off. When receiving the reset or time up signal, cut off the boost circuit power supply.

(3) Display circuit

The display shows the output voltage value of the step-up transformer. Display the current value of the current sampling part, and the time value of the time circuit is generally.

(4) The above is the structure of the traditional withstand voltage tester. With the rapid development of electronic technology and single chip, computer technology; Program-controlled withstand voltage tester has also developed rapidly in recent years. The main difference between program-controlled withstand voltage tester and traditional withstand voltage tester is the boost part. The high-voltage boost of the programmable withstand voltage meter is not regulated by the voltage regulator through the mains, but a 50Hz or 60Hz sine wave signal is generated by the single-chip computer control, and then amplified and boosted by the power amplifier circuit, and the output voltage value is also controlled by the single-chip computer. It is controlled by a chip computer, and the principles of other parts are not much different from the traditional withstand voltage meter.

The basic principle of the withstand voltage tester: Apply a higher voltage than the normal working voltage to the insulator of the device under test for a specified period of time. If the insulation in between is good enough, the voltage applied to it will only produce very high voltage. Small leakage current. If an insulator of a device under test maintains its leakage current within a specified range within a specified period of time, it can be determined that the device under test can operate safely under normal operating conditions.