Passenger Elevator

Overview

A passenger elevator carries people between floors of a building inside a guided car. This is a gearless machine-room-less (MRL) traction design, the standard for low- and mid-rise buildings: the hoist machine is small enough to sit in the shaft itself, so no separate machine room is needed above the well.

The car hangs from steel ropes that pass over a grooved sheave on the Gearless Traction Machine and down to a Counterweight. The counterweight balances the empty car plus about half its rated load, so the motor only ever has to move the imbalance rather than the full weight. Because the ropes grip the sheave by friction, the system is called a traction elevator. Car and counterweight both run on machined steel Guide Rail Set that keep them aligned and give the safety gear something to clamp.

Above the cabin sits the everyday machinery the rider interacts with, the Car Door Operator that slides the doors, the call buttons, and the position display, all wired back to a cabinet through the festooned Traveling Cable.

How it works

When a hall button is pressed, the Group / Car Controller dispatches the nearest suitable car. It releases the brake and commands the VFD Drive, which feeds the permanent-magnet motor with a precisely shaped current so the car accelerates, runs at speed, and decelerates along a smooth ride profile. A shaft encoder in the Position & Leveling Sensors package tells the controller exactly where the car is, and magnetic floor vanes let it stop level with the landing within a few millimetres.

At each floor the car door and the matching Landing Door are coupled and driven open together by the single car-mounted operator. The landing door carries an interlock wired into the safety chain: the elevator cannot move unless every door is proven shut and locked, and a light curtain reopens the doors if anyone breaks the threshold.

Safety is layered and mechanical. The Overspeed Governor continuously watches car speed; if the car ever overspeeds downward it first drops an electrical contact, then physically grips its rope to trip the wedge safety gear, which clamps the guide rails and stops the car. Spring-applied brakes on the machine hold the car whenever power is removed, and oil/spring buffers in the pit absorb the impact if a car ever overtravels its lowest stop.