How to achieve strong anti-interference ability of needle detector

There will always be certain interference factors in the use of needle detectors in toys, clothing and other products, but how does our needle detector achieve this anti-interference ability? Because a closed rectangular frame is used as a magnetic circuit , greatly reducing the leakage of magnetic flux. At the same time, a shielding layer is installed outside the rectangular frame.

The single-phase AC asynchronous motor is used instead of the DC motor for transmission, and the length of the transmission bracket is lengthened, so that the motor is not less than 1.5 m away from the detection head part, so as to reduce the interference of the motor magnetic field. In addition, the circuit has a strong ability to suppress common mode signals. The signal produced by the 2mm tip is very weak. In order to improve the detection sensitivity, it is necessary to strengthen the magnetic field, increase the number of coil turns, and increase the gain of the amplifier circuit. The static electricity carried by the inspected items such as toys will cause the needle detector to falsely alarm. In order to eliminate the influence of static electricity, an anti-static conveyor belt is used, and static electricity is introduced to the frame through a metal rotating shaft and discharged to the ground through a grounding wire.

It can be seen that the needle detector, as a detection tool, has a very high actual technical content. It is not something that can be replaced by ordinary products, nor can it be successfully developed by ordinary small manufacturers.