What instrument and method can be used to measure the contact resistance of metal surfaces?
The DHL-100A loop resistance testing instrument with high frequency switching power supply circuit and digital processing technology combined with the technique of design, DC 100A test current recommended by national standard test, DHL-100A loop resistance testing instrument for measuring equipment to the switching control circuit resistance, resolution up to 1U, can be directly measured in the current loop 100A the case, data display and intuitive, clear, DHL-100A loop resistance testing has the advantages of accurate measurement, stable performance, simple operation, with the power supply department, the scene switches using the factory loop resistance testing requirements.
The DHL-100A loop resistance testing instrument is Wuhan Ding Sheng Electric Power Ministry according to the standard SD301 - 88 "AC 500KV power equipment installation and preventive test procedures" and the new version of "preventive test code for electric power equipment" made for circuit breaker isolating switch contact resistance measurement of DC current is not less than 100A, to ensure accurate test results. In 2004, Wuhan Ding Sheng Electric Power Co., Ltd. R & D center in accordance with People's Republic of China's latest power implementation standards DL/T845.4-2004 and on-site specifications for research and development.
The resistance to contact between conductors is called contact resistance. Contact resistance is generally required to be below 10-20 MOhm, and some switches require less than 100-500uohm. Some circuits are sensitive to changes in contact resistance. It should be pointed out that the contact resistance of the switch is the maximum allowable contact resistance of the switch in several contacts. A contact resistance test is designed to determine the resistance produced by an electric contact of an electric current passing through the contact surface of the contact. One of the contact resistance test method in GB5095 "electromechanical components for electronic equipment - Basic testing procedures and measurement methods", "contact resistance - MV law" stipulates that in order to prevent the contact film breakdown testing circuit of AC or DC open circuit peak voltage should be not greater than 20mV, current AC or DC test should not more than 100mA.
To measure the contact resistance of high voltage circuit, it is necessary to use the loop resistance tester.
