A 3‐D SPACE ANALYSIS OF AN ELECTROMAGNETIC FIELD IN A THREE PHASE INDUCTION PUMP WITH A COMPENSATING WINDING

Three‐phase inductors with a magnetic travelling field are often used to pump a liquid metal or to stir it in induction stirrers. Due to a finite length of inductor an alternating magnetic field is generated as an additional component to the magnetic travelling field. When an induction pump is used with a rectangular shaped transport channel and a flat inductor shown in Fig.1,this component deforms a force distribution in liquid metal and causes some local whirls. This may play a positive role in stirring of molten metal but it cannot be tolerated in the channel of an induction pump,where a smooth flow is required. In that case the alternating magnetic field should be eliminated. It can be done by using an additional compensating winding or by applying a special type of three‐phase winding that eliminates or reduces the alternating field component. The objective of this paper is to examine the magnetic field and force distribution in molten metal of an induction pump when the alternating magnetic field component is compensated.