In the vertical transportation industry, the Otis Gen2 elevator system is widely respected for its space-saving design, energy efficiency, and the use of flat, polyurethane-coated steel belts (PBS belts) instead of traditional steel ropes. However, experienced maintenance mechanics and building managers have become increasingly familiar with a specific acoustic phenomenon: the dreaded Otis Gen2 scratch.
Mark the edge of the belt with a piece of white chalk. Run the car for 10 feet.
Flat Steel Belts: Unlike traditional round ropes, the Gen2 uses flat, polyurethane-coated steel belts.
M-1-3-1 (fault history)M-2-2-1 (belt wear counter)Machine-Roomless (MRL): The machinery is typically housed within the elevator shaft itself, saving space. Search Tips for Scratch
Sheave Misalignment: Can cause fraying or cracking on just one edge of the belt.
Before you can clear the noise, you must identify the root cause. Below are the top five reasons for a mechanical scratch in the Otis Gen2 platform.
Always isolate the sound. Use a mechanic’s stethoscope or a wireless listening device. If the scratch changes pitch when you load the car, it is belt/sheave. If it changes with direction only, check the brakes.