What the brake does
A failsafe brake holds a load when power is lost — main hoist brakes, storm brakes, rail clamps. A service brake decelerates a moving drive — conveyor head pulleys, gantry travel. Pick the failsafe type first; service brakes are usually thruster-released drum or disc.
Sizing torque
Required braking torque is typically 1.5–2.5× the rated motor torque referred to the brake shaft, but ports, mines and steel mills have their own multipliers — for STS crane main hoists use 2.5×, for conveyors 1.5×, for slewing 1.75–2×.
Disc vs drum
Disc brakes give the highest energy dissipation per kilogram and the most repeatable response — best for high-cycle service and emergency duty. Drum brakes shed heat into a large mass, simple to overhaul, and remain the workhorse for thruster-released conveyor and crane brakes.
Thruster vs electromagnetic
Hydraulic thrusters are the standard release device on heavy industrial drum and disc brakes — robust, slow, energy-efficient. Electromagnetic release suits smaller motor-mounted brakes where fast response matters.
Environment
IP rating, corrosion class, ATEX, ambient temperature and salt-fog exposure all drive material and seal choice. KZN coastal and port duty require at least IP56 stainless / e-coat protection.