Application scenarios of safety testing equipment
The use of safety testing equipment is widespread, mainly applied in the manufacturing, maintenance, and related research of various electronic devices. Common application scenarios include power supply, LED lighting, household appliances, medical equipment, communication equipment, industrial automation, automotive electronics, new energy and other fields. In these scenarios, the role of safety testers is crucial because only accurate and comprehensive testing can ensure that the products produced meet the electrical safety standards set by the country and industry.
The testing content of the safety tester
Generally speaking, the testing content of a safety tester mainly includes the following: AC withstand voltage, DC withstand voltage, insulation resistance, grounding resistance, leakage current, load power, low-voltage starting, short circuit testing, etc. However, there are also specific testing contents that need to be carried out for a particular field. Let’s explain one by one.
1. Voltage endurance testing: Apply a high voltage of several thousand volts (AC or DC) between the casing or easily accessible parts of the tested electrical device and the power input terminal to detect the amount of leakage current under such high voltage. When the leakage current exceeds a certain value, it may cause harm to the human body.
2. Leakage current detection: divided into dynamic leakage and static leakage.
(1) Static leakage: Apply 1.06 times the rated working voltage between the shell of the tested electrical appliance and the easily accessible parts of the human body, respectively, and the live and neutral terminals of the power supply to detect the maximum leakage current. At this time, the tested electrical appliance does not work. The applied 1.06 times voltage should be provided through an isolation transformer.
(2) Dynamic leakage: Conduct the same detection as static leakage (also known as thermal leakage) while the tested electrical device is running with power supply.
(3) When choosing a leakage current detection instrument, the focus should be on selecting the input impedance of the leakage current and the capacity of the isolation transformer. The input impedance of the tester requires simulating the impedance network of the human body. Different electrical product standards have different human body network models, which should be selected correctly. The corresponding national standards include GB9706 GB3883、GB12113、GB8898、GB4943、GB4906、GB4706。 The capacity of the output isolation transformer of the leakage current tester should be suitable for the measured capacitance. When the tested electrical device is a motor or the like, and its starting current is several times higher than the rated current, it should be considered based on the starting current.
3. Insulation resistance detection: Apply a direct current voltage (usually 1000V, 500V, or 250V) between the casing or easily accessible parts of the tested electrical device and the power supply input terminal, detect the leakage current at this voltage, and convert it into insulation resistance.
4. Grounding resistance test: Apply a constant high current (usually 10A or 25A) between the tested electrical appliance casing and the grounding terminal to detect the conduction resistance under this current. Excessive resistance does not provide grounding protection.
Post time: Aug-09-2024
