an improved eddy current braking system for fly wheel braked exercise equipment includes the use of a flat aluminum disc and electromagnets to either side of the disc adjacent to the periphery thereof , with the electromagnets containing multiple pole pieces to multiply the torque so as to reduce heating and power consumption . the utilization of aluminum achieves a flat torque versus speed characteristic vis - a - vis copper discs over the normal operating speed range . additionally , the utilization of aluminum prevents the warpage associated with copper .