Nowadays, with the diversified needs of application requirements, the form of needle detector has been developed and extended to more specifications. For example, the slot needle detector applied to shoe material detection. The working principle of needle detector the magnet and needle coil in the upper and lower magnetic heads form a working magnetic field of needle detector by the power supply connected to the machine. When iron chips and other foreign substances with iron properties enter the needle detector area, the local magnetic field environment will change And then cause the fluctuation of local magnetic field instantaneous current. The sensed abnormal current will be transmitted to the control circuit board and compared with the previously set needle sensitivity; When the current value of this change reaches or exceeds the needle sensitivity value set when the equipment is in use, the control circuit board will give a series of commands such as alarm, stop and belt reversing to the machine; And finally complete these actions.
