A comparison of distributed and concentric windings in linear induction pump for liquid metals

In this paper a calculation of the driving force in linear induction pumps is presented. The model used for the pump consists of an array of single turn coils which carry balanced polyphase currents. The coils have rectangular shape such that their dimension along the array length is much smaller than their dimension along the transverse direction. The metal is considered to be at rest and the secondary reaction is neglected. Closed form expression is obtained for the driving force. Results are presented for the force as a function of the air gap for a number of array lengths. The behaviour of the concentric windings is compared to that of the distributed windings. The calculations show that the force decays more rapidly with the air gap when the dominant wave length of the field-waves is smaller. The concentric windings have a smaller force than the distributed windings.