Fast Turn-off Mine Transient Electromagnetic Transmitter System

• Main Author: ZHENG Xiao-Liang
• Format: Article
• Language: English
• Published: IFSA Publishing, S.L. 2014-05-01
• Series: Sensors & Transducers
• Subjects: Transient electromagnetic; Coal mine; Transmitter current; Fast turn-off.
• Online Access: http://www.sensorsportal.com/HTML/DIGEST/may_2014/Vol_170/P_2056.pdf

For solving problems such as short turn-off time, high linear degree of falling edge, measurement of turn-off time and influence of primary signals for transient electromagnetic transmitter, and restrictions because of the environmental conditions of underground coal mine, this thesis aims at designing a new transient electromagnetic transmitter system suitable for coal mine. Supported by damping absorption circuit, such system applies small volume, sectional transmitting coil, with features of short turn-off time, high linear degree of current falling edge. It uses the transmitter monitoring circuit, which accurately measures turn-off time and simultaneously records the current value changes after turn-off, thus to eliminate the influence of primary field as well as to restore earlier secondary field signals for reference and finally to improve the ability to detect the shallow structure. It turns out that the new system has a shorter turn-off time, a higher linear degree of current falling and more accurate data record of turn-off current.