Home Elevator

Overview

A home elevator is a small passenger elevator designed for private residences, where the constraints are the opposite of commercial practice: travel is short (two to five stops), traffic is light, and the building offers no machine room, no deep pit and often only a single-phase power supply. The dominant modern configuration is machine-room-less gearless traction. A compact permanent-magnet Gearless PM Machine sits on the guide rails in the shaft headroom, drives the cab through coated flat belts, and the entire installation fits a shaft of roughly 1.4 × 1.5 m with a pit only 200–300 mm deep. Hydraulic and screw-drive variants exist, but belt-traction units dominate new installations because they run on a 230 V single-phase supply, need no oil and are the quietest of the three.

Rated load is typically 400 kg, five persons, or one wheelchair user with an attendant, at 0.15–0.3 m/s. Residential codes (EN 81-41 in Europe, ASME A17.1 Section 5.3 in North America) permit these low speeds and in exchange relax some commercial requirements, which is what makes the shallow pit and reduced headroom possible.

Drive and suspension

The Gearless PM Machine is a gearless permanent-magnet synchronous motor of 1.5–2.2 kW. Sixteen Neodymium Magnet poles on the rotor allow high torque at very low shaft speed, so no gearbox is needed; an Encoder closes the velocity loop. Because the machine hangs from the rail tops rather than a machine-room floor, its mass and the suspended load pass straight down the rails to the pit.

Suspension is the most distinctive element. Instead of round wire ropes, the Belt Suspension uses three flat Coated Steel Belts, polyurethane-jacketed bands about 30 mm wide containing parallel high-tensile steel cords. The jacket grips the Traction Sheave by friction without grooves, and because the belts tolerate bend radii far tighter than rope, the sheave can be only about 100 mm in diameter, which is what lets the whole machine shrink enough to fit inside the shaft. Each belt ends in a wedge-clamp Belt Termination, and a Belt Monitor passes a sense current through the cords to flag broken strands long before failure, replacing the visual rope inspection of conventional elevators. Two independent spring-applied Disc Brake circuits hold the machine, satisfying the redundancy demanded by EN 81-41.

Cab and shaft

The Passenger Cab hangs from a bolted Cab Sling riding two T50/T70 rail lines of the Guide Rail System system on polymer-gibbed Guide Shoes. The Cab Floor carries the load-weighing sensors; the Cab Ceiling integrates LED lighting and the required emergency light. A two-panel telescopic Car Door closes the cab opening, protected by an infrared Light Curtain rather than a mechanical safety edge.

Each floor has a Landing Door, usually a side-hinged Door Leaf in a steel Door Frame, chosen because a swing door can be finished like ordinary interior joinery and needs no header mechanism. A hydraulic Door Closer returns it shut, and the Door Interlock enforces the same rule as in any elevator: the door stays locked unless the cab is level at that floor, and the cab cannot move while any door is open.

Safety and power failure

At 0.3 m/s and below, codes permit instantaneous Safety Gear: cam-type grippers on the sling that bite the rail blades when the Overspeed Governor trips, stopping the cab within a few centimetres without the progressive-braking machinery a faster elevator requires. Solid polyurethane Pit Buffers in the shallow pit handle terminal overrun. Power failure is treated as a normal event rather than an emergency: the Controller carries an 12 V Battery pack sized to release the brakes and run the drive long enough to lower the cab to the nearest landing and open the doors, so no occupant is ever trapped by an outage.

Control

The Controller is a single wall cabinet. A small inverter built from six IGBT Power Modules rectifies the single-phase supply and synthesises three-phase output for the PM machine, ramping it through soft jerk-limited profiles; peak draw stays within a domestic 16 A circuit because the counterweighted load rarely demands more than about 2 kW. Safety-chain Relay contactors, the belt monitor input, door interlocks and the Car Operating Panel all terminate on the logic board, with the Traveling Cable linking the moving cab. A two-way intercom or GSM dialler in the cab is mandatory under both EN 81-41 and A17.1, since a home elevator cannot rely on building staff to answer an alarm.