number of loops or spires depends on the energy consumption of electrical and or electromechanical mechanism 5 to be powered for example an lcd display screen requires 100 mw and a motor to drive mobile bit 2 a of the fixation means requires 6 w therefore a single loop to recover 20 w is necessary in one possible implementation terminals 10 and 10 u2032 of handle 1 are electrical contact plates 23 pushed by elastic recall means 24 as shown in fig6 and 7 they limit contact resistance to less than 100 momhs and preferably to less than 10 momhs thereby significantly improving yield each electrical contact plate 23 is elongated in shape and has a circular cross section each electrical contact plate 23 has a cross section of at least 0 75 mm 2 to resist a current of at least 0 5 a and preferably 3 a each electrical contact plate 23 includes head 26 on one of its extremities which is designed come into contact with terminal 11 and 11 u2032 of pot 3 and more specifically with electrical connection 19 a and 19 b of pot 3 this head 26 is preferably rounded or convex each electrical contact plate 23 is located in cylindrical support 39 and can move.