Maintenance, Service, and Repair of Conveyance Equipment
Domain focus
Maintenance, service, and repair tests planned inspection and troubleshooting on traction and hydraulic elevators and escalators: brakes, ropes, sheaves, governors, safeties, door operators, valves, controllers, step chains, handrails, and comb plates. Expect questions on what to inspect, how to test, and when a component is removed from service.
Core rules and concepts
- Establish safe control: lockout/tagout, verify zero energy, use car-top inspection controls, and barricade the hoistway or escalator landing.
- Brakes: check lining wear, drum condition, spring condition, and set gap. A gap outside manufacturer's range changes drop time and stopping distance.
- Ropes: inspect for broken wires, corrosion, diameter loss, elongation, and damaged end fittings. Use the rope manufacturer's retirement criteria and the applicable code; do not judge by appearance alone.
- Doors: verify clear opening, closing force, reopening device, gibs, rollers, and restrictor. Door faults are a leading cause of callbacks.
- Hydraulics: check oil level and condition, valve operation, packing leakage, and relief valve setting; do not adjust relief valves without the correct procedure and gauge.
- Escalators: inspect step chain elongation, step rollers, handrail speed and alignment, skirt panels, comb plates, and stop switches.
Worked example
A brake feeler gauge shows 0.025 in gap; the manufacturer specifies 0.010-0.015 in. The gap is too large, so the armature travels farther before seating, increasing drop time. Adjust the gap to mid-range, then test brake set and release, monitor stopping distance, and record the result. Do not close the gap below minimum to "make it grab."
Traps
Replacing a rope because of one broken wire outside the lay; adjusting a relief valve to cure slow speed; testing safeties without verifying governor trip speed; and cleaning escalator comb teeth rather than replacing a worn or damaged comb.