Research Of Equipment Based On Virtual Insrument For Electrical Contact Test Of Relay And Its Experiment

42VDC power supply is the new electrical level for the future generation automotive relays. The high voltage 42V will cause great changes to electrical contact performance of relays. At present ,the research on influence of development of supply voltage on electrial contact performance of relay focuses on test study. However, the lack of test data and different test conditions make it hard to do further research.In this thesis, an electrical contact test equipment of relay is built with the technique of virtual instrument. This test equipment can control the whole process of test, sample and store the test data automatically; as a component of the test equipment, the data acquisition card has features of 12-bit analog input resolution and up to 330K A/D sampling rate; the doubble buffer mode is used to sample and store real-time data continously; with the 528MB/s PCI bus transmission rate of the data acquisition card, the test data can be transfered to the hard disk of PC directly, which solves the problem of capacity of the data storage; the method of indexing storage is adopted to simplify the management and analysis of data.In order to examine the validity of the performance of the test equipment, electrical contact tests are performed respectively with commercial relay and simulation test device at the same DC current respectively under three DC supply voltage levels; the signals of arc voltage and arc current obtained from the electrical contact tests are displayed real-timely and stored continously; with the programs of LabVIEW, many parameters, such as arc duration, close bounce, are extracted from the test data and analized. According to the result of the electrical contact tests, the test equipment is available for the test study of electrial contact performance of relay.