a hysteresis brake including a casing having internal alternating first slots and first teeth , a pole having external alternating second slots and second teeth , a rotor including an annular portion located in spaced relationship between the casing and pole , and structure for permitting the pole and casing to be rotationally adjusted relative to each other and to lock the first slots and teeth of the casing in a rotationally adjusted position relative to the second slots and teeth of the pole to cause the brake to provide a torque output of a substantially predetermined value at a predetermined current . a method of calibrating a hysteresis brake to provide a torque of a substantially predetermined value at a predetermined current including the steps of rotating the casing and pole relative to each other to a position which provides substantially the desired torque at the predetermined current , and locking the casing and pole to each other in that position .