High Performance Mine Transient Electromagnetic System and Applications

This thesis introduces structures and main key technologies of high performance transient electromagnetic system of mine. Such system applies sectional transmitting coil with damping absorption circuit to shorten turn-off time, thus achieving linear falling edge of transmitter current; inspects the turn-off time and current falling edge to enrich essential data of primary field; uses programmable and variable receiving coil to provide different selection modes to solve influence of transient process; and also takes advantages of the pre-amplification and programmable amplification circuit and variable settings of sample period to solve the accurate collection problem for different period signals in secondary field. It provides detection layout and result of application examples proving good test effect and superior