Leakage current is relatively small, generally zero point a few milliamps, such as 220VAC/0.42ma. Leakage current is relatively large, half of a few milliamps to dozens of milliamps, such as 2000VAC/5ma, there are also leakage current have to ask for a very high level of application occasions, such as medical power supply, only zero point a few milliamps.
Leakage current refers to the absence of faults in the case of the applied voltage, the electrical band with mutual insulation between the metal parts, or between the charged parts and grounded parts, through its surrounding medium or insulating surface of the current is called leakage current. And leakage current is divided into four kinds, respectively: semiconductor components leakage current, power leakage current, capacitor leakage current and filter leakage current.
Leakage current consists of two parts, one is through the insulation resistance of the conduction current, the other part is through the distribution of capacitance of the displacement current, the latter capacitive resistance XC = 1/2pfc with the power supply frequency is inversely proportional to the distribution of capacitance current with the frequency increases, so the leakage current with the power supply frequency increases. For example: with silicon controlled power supply, its harmonic component of the leakage current increases.
Expanded information:
Leakage current measurements are used to measure the leakage current of an electrical device. p>The power supply used in leakage current measurement is generally supplied by a high-voltage test transformer or a series resonant voltage withstand device, and the leakage current is read directly by a microampere meter. It is compared with the insulation resistance measurement has characteristics: high test voltage, leakage current can be monitored by the microampere meter at any time, high sensitivity, measurement repeatability is also better.
Leakage current is actually electrical lines or equipment in the absence of faults and the role of the applied voltage, the current flowing through the insulation part. Therefore, it is one of the important signs to measure the insulation of electrical appliances, dare is the main indicator of product safety performance.
Communication power supply leakage current requirements. In the leakage current is greater than 3.5MA, the leakage current should not exceed 5% of the input current of each phase, if the load is unbalanced, the maximum value of the three phase currents should be used for calculation. The steady state leakage current of the power supply module meets the national YD731 standard, the leakage current under 1500VAC should not exceed 30mA, and the leakage current under 220VAC should not exceed 5mA.
Baidu Encyclopedia - Leakage Current
Baidu Encyclopedia - Leakage Current