of the rotor and magnet positioning device and fig1 shows a cutaway view of the same combination as in the embodiment shown in fig8 to 10 the rotor 150 is mounted on a shaft 152 and includes four magnets 154 however in this embodiment the magnet positioning device 156 includes connecting clips 158 spaced around the periphery of the body of the positioning device 156 to attach it to the rotor 150 the magnet positioning device 156 also includes locating pins 160 which engage in corresponding apertures 162 in the rotor 150 the magnet positioning device 156 further includes an annular groove 164 to enable weights to be inserted and retained therein so as to enable any imbalance in the rotor 56 to be corrected the method of assembly of the rotors shown in fig8 to 10 and 11 to 15 is the same as the method involved in the assembly of the embodiment shown in fig1 to 7 referring now to fig1 to 19 there is shown a further embodiment of the present invention as applicable to a linear motor fig1 shows a rotor for the linear motor in this type of motor the term u201c rotor u201d should be interpreted broadly to mean the moving part of the motor clearly the rotor does not rotate in this instance but instead travels linearly with respect to a stator of the linear motor the rotor 350 includes permanent magnets 354 fig1 and 18 show top and bottom perspective views respectively of a magnet positioning device 356 in accordance with an embodiment of the present invention the magnet positioning device 356 includes recesses 358 therein for receiving corresponding magnets 354 as shown in fig1 although preferred embodiments of the invention.