## 2 Basic Structure and Operating Principle of the Three-Phase AC Magnetic Separator  
### Basic Structure of the Three-Phase AC Magnetic Separator  
The three-phase AC magnetic separator utilizes the effect of the traveling wave magnetic field to discriminate the magnetic material. Under the action of the alternating magnetic field, the phenomenon of \"flocculation\" does not occur, the separation effect is good, the device structure is simple, and the separation amount is large.  
The three-phase AC magnetic separator is designed based on the three-phase AC flat linear motor, which is composed of a 0.5 mm thick silicon steel sheet (DW465-50, Manufacturer name, city, state if US or Canada, country) with a stacking coefficient of 0.9. The basic structure is shown in Figure 1. The stator slot adopts an open slot, and the slot is filled with three-phase windings. The currents of the three-phase windings are equal in magnitude, but the difference between phases is 120 degrees. The stacking form is double-layered winding. The inner diameter of the enameled wire is 1 mm and the outer diameter is 1.062 mm. After the assembly is completed, the resin is sealed in the metal casing, and the surface of the device is covered with 3 mm wear-resistant ceramic. The three-phase AC magnetic separator is divided into two zones (unloading zone and adsorption zone), and three-phase symmetric windings are arranged under the wear-resistant ceramic in the adsorption zone. There is no winding under the wear-resistant ceramic in the unloading zone. The specific parameters of the three-phase AC magnetic separator are shown in Table 1.  
The Installation diagram of the three-phase AC magnetic separator is shown in Figure 2. The device is installed in the unloading end of the belt conveyor in the original pulverizing system of the power plant. The pulverized coal falls to the adsorption zone of the three-phase AC magnetic separator at a certain speed. Under the action of gravity, the pulverized coal and other diamagnetic substances follow the adsorption zone falls. The magnetic substance reaches the unloading zone from the adsorption zone under the action of the electromagnetic force generated by the three-phase traveling wave magnetic field, and there is no magnetic field in the unloading zone, so the magnetic material falls under the action of gravity. Therefore, the separation of diamagnetic material such as coal powder and magnetic material is realized. The finely ground coal is uniformly and loosely rolled on the surface of the desulfurization device to facilitate adsorption, and the magnetic field strength of the desulfurization device is greatly reduced, which is beneficial to energy conservation.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Parameter** & **Numerical Value** & **Parameter** & **Numerical Value** \\ \hline Total length L\({}_{\text{s}}\)/mm & 486 & Total width W\({}_{\text{s}}\)/mm & 84 \\ Total height H\({}_{\text{s}}\)/mm & 50 & Slot width W\({}_{\text{ss}}\)/mm & 6.8 \\ Slot depth H\({}_{\text{ss}}\)/mm & 35 & Tooth width W\({}_{\text{sp}}\)/mm & 4.87 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Three-phase alternating current (AC) magnetic separator parameters.  
Figure 1: Schematic diagram of the three-phase alternating current (AC) magnetic separator.