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Test Analysis Of Pressure Tester
- Apr 23, 2018 -

The test value of AC and DC is different.

The basic principle of withstand voltage tester: add a higher than normal working voltage in the equipment to be tested on insulator, and continue for a period of time, the insulation good enough if the meantime, in the above voltage is only a small leakage current is produced. If a device being tested insulators within the prescribed period of time, the leakage current to keep within the prescribed scope, can determine the device under test can be safe operation under normal operating conditions as a result of the stray capacitance of measured object with different values measured in AC and DC withstand voltage test of the main reasons.

The stray capacitance may not be sufficient for AC testing, and a continuous current flows through these stray capacitors. Analyte with DC testing, once the stray capacitance on the charge, the rest is the actual object is test the leakage current, so use AC withstand voltage test and DC withstand voltage test the leakage current value measured by there will be different

The maximum output voltage value and maximum alarm current value must be greater than the voltage value and alarm current value you need. In general, the high voltage value and alarm value are specified in the product standard. If the applied voltage is high, report to the police to determine the current, the greater the pressure meter is necessary step-up transformer the greater the power, the general pressure gauge step-up transformer power 0.2 kVA, 0.5 kVA, 1 kVA, 2 kVA, 3 kVA, etc. The maximum voltage can reach tens of thousands of volts. Maximum alarm current 500ma-1000ma, etc. So you must pay attention to these two indicators when choosing a pressure - resistant device. Too high power selection will result in waste, too small pressure test can not be judged correctly or not. According to IEC414 or (gb6738-86), the power method of selecting the pressure-proof device is considered as the scientific method. "First of all the pressure gauge, and 50% of the output voltage is transferred to the specified value and then connected to the participants to taste, when the observed voltage drop less than 10% of the voltage value, think the power of pressure gauge is enough."

that is, if a product of the pressure test voltage is 3000 v, the pressure gauge first after the output voltage to 1500 volts of connected to the participants to taste, if the pressure gauge output voltage drop value is not greater than 150 v, so the power of pressure gauge is enough. There is a distributed capacitance between the charged part of the specimen and the shell. The capacitor has a CX tolerance, and when an ac voltage is applied to the CX capacitor, the two ends of the capacitor are turned into an electric current.

The size of the current is proportional to the CX capacitance capacity is proportional to the applied voltage, when the current is too big to or exceed the pressure meter maximum output current, the pressure gauge can't correct discrimination test or not.