Relay Magnetic Circuit Parts Coercivity Of Automatic Test System Design And Implementation

The magnetic accessory has the key effect in electromagnetic relay. The performance of magnetic accessory is the important means to ensure the quality of electromagnetic relay products.The traditional instruments can used to measure the big size sampled accessory, but can not ensure the veracity of the small magnetic accessory used in relay. Instrument of this type is too rich overseas.Based on the study of coercivity measurement methods, the new scheme was bring up. The scheme based on air vibrancy winding measurement, combines the technology of Virtual Instrument, then uses phase measurement to implement the auto measurement of coercivity. Build the hardware platform system with the DAQ card USB-6009 and several related hardware circuits; accomplish the work of the tested software. This system has merit of the high measurement precision, easy to upgrade and maintenance.The development of the auto test system based on the method of cooperation with hardware and software, the system is divided into two parts which include system hardware design and test software design. The hardware includes sensor signal conditioning circuit, low frequency oscillation circuit, and constant current source circuit and the circuit of relay control, ect. The software includes the initialization of system, design of data acquirement and management, control of D/A and phase measurement, the program and interface of the system. Then through several experiments, modification and debug, finally realize the measurement of coercivity of relay magnetic accessory through the auto test system. Via the validation of performance and precision in this system, we make sure that the system reaches the initial target of the design, the test result fulfill the requirements.