i assume you have the style that has the coil mounted on the side in a large cast iron box if it is on the side of the coil is the prime shoe you adjust that one first for lift on the top of the brake there are 2 adjustments the star shaped knobs are tension and the the knob at the outside adjusts the secondary shoe lift the knob between the coil housing and the primary shoe is the lift for adjustment for the primary shoe adjust that first then adjust the secondary shoe lift last is tension do not try to put too munch lift in as the brake will not pick at all lastly
the these brakes were designed originally to be oil bath 3 phase ac some of the later ones had dc coils if it has 3 wires going to it it is an ac brake and requires oil hope this helps
