During an emergency stop, an overhead crane or gantry crane brake must engage quickly, deliver predictable deceleration, and hold the load without excessive slip. Key metrics usually include response time (command to brake torque), stopping time/distance, and maximum allowable load drift (especially for hoisting). For hoist brakes, the priority is preventing uncontrolled lowering—so a fail-safe brake (spring-applied, power-released) is the baseline requirement.
In VFD-controlled systems, E‑Stop performance also depends on coordination: drive torque should be removed or ramped appropriately while the mechanical brake applies at the correct timing to avoid shock loads or hook bounce. Testing should be performed under controlled conditions and representative loads, with documentation for compliance and audits.
A brake that meets torque on paper can still fail E‑Stop expectations if it overheats, drags, or has excessive air gap. Always evaluate emergency stopping as a complete system function.