Metal separators apply the principle of electromagnetism to detect metals. All metals, including iron and non-iron, have high sensitivity. Ferromagnetic metals entering the detection area will affect the distribution of the magnetic line of force in the detection area, thus affecting the magnetic flux in a fixed range. Non-ferromagnetic metals entering the detection area will also produce eddy current effect and change the magnetic field distribution in the detection area.
Usually a metal separator consists of two parts, namely, a metal separator and an automatic culling device, in which the detector is the core part. Inside the detector are three sets of coils, namely, the central transmitting coil and two equivalent receiving coils, A high-frequency variable magnetic field is generated by an oscillator connected by a transmitting coil in the middle. In idle state, the induction voltage of the receiving coil on both sides of the receiving coil cancels each other before the magnetic field is disturbed and reaches equilibrium. Once the metal impurity enters the magnetic field, the magnetic field is disturbed, the balance is broken, the inductive voltage of the two receiving coils cannot be offset, the unoffset inductive voltage is amplified by the control system, and an alarm signal is generated. The system can use the alarm signal to drive the automatic culling device to reject the metals.