Cooling method of periodic pulse-type linear induction motor armature

A linear motor is a critical component of the electromagnetic launch system (EMALS). The linear motor mainly consists of stators and armature. To meet the requirements of the EMALS, the stator is composed of many segments in series. The traveling magnetic field is generated when the block-feeding stator windings are turned on, and then the electromagnetic force is induced in the armature, which accelerates the load. Since the electromagnetic force leads to severe heating problem of the armature, it is important to cool the armature. According to the working conditions and requirements of linear motor in the EMALS, this paper has made a detailed analysis of the effects of the natural air cooling, forced air cooling and spray water cooling on the linear motor armature. Based upon the analysis it is concluded that the spray water cooling is the best method. Through the equivalent test on the armature, the spray cooling method is proved to be so effective as to satisfy the requirements of continuous operation of the EMALS.