provide a counteracting and distributed normal force over the same wrap angle u03b1 the interaction of the opposing contact and normal forces exerted on the piezoelectric layer 30 will generate electrical energy accordingly in operation as the piezoelectric layer 30 rotates it will have minimal compression while located in the lower semi circular travel segment of the traction sheave 14 however as the tension member enters into engagement with the traction sheave 14 the compression exerted on the piezoelectric layer 30 progressively increases to a maximum compression in the upper travel region of the traction sheave 14 thereafter the compression exerted on the piezoelectric layer 30 progressively decreases to the minimal compression once again when the tension member 6 disengages with the traction sheave 14 the rated speed of a traction sheave 14 will vary widely depending on application typical factors that are taken into consideration include sheave diameter wrap angle u03b1 rated load travel height roping ratio and tension member type consequently the traction sheave 14 may have a rated speed ranging from the tens to the hundreds of revolutions per minute rpm given firstly the relatively high rotational speed of the traction sheave 14 and secondly the substantial compressive force differentials exerted on the piezoelectric layer 30 during each rotation of the traction sheave 14 a significant and reliable supply of electrical energy can be generated by.