What is the difference between a geared and gearless elevator machine?

A geared machine uses a worm or helical gearbox between a high-speed motor and the sheave; it is compact and economical for low-rise duty but needs oil changes. A gearless permanent-magnet machine drives the sheave directly, is quieter and more efficient, and is the basis of machine-room-less installations.

How do I select an elevator traction machine?

Selection combines rated load, rated speed, roping ratio, total suspended mass, sheave and groove profile matched to the rope diameter, brake torque with 125% load, and controller compatibility. Liftech issues a machine-selection sheet with the traction and shaft-fit calculation.

Can a VVVF drive be retrofitted to an old elevator?

Yes. Replacing a two-speed or ACVV drive with a closed-loop VVVF inverter and encoder typically improves levelling to ±1 mm, cuts starting current and removes floor-stop jerk — often without changing the machine, provided the motor and brake are serviceable.

How much energy can a regenerative elevator drive save?

On buildings with steady traffic, a regenerative drive returning braking energy to the supply typically saves 20–40% of lift energy consumption compared with a resistor-braked drive; the saving is highest on high-rise cars with heavy counterweight overhauling.

What brake does EN 81-20 require on a traction machine?

EN 81-20 requires two independent braking circuits, each individually able to hold and decelerate the car at 125% of rated load, with monitoring switches proving that each brake releases and re-applies.

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Parts · PRT-03

Elevator Traction Machines & Drives

Gearless PM machines, geared machines and VVVF inverter drives from 320 kg to 5 000 kg.

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Torin Drive GTW9A gearless permanent-magnet elevator traction machine with twin DC brakes — PRT-03 · Elevator Traction Machines & Drives

PRT-03

In short

An elevator traction machine is the motor and sheave assembly that drives the suspension ropes or belts. Gearless permanent-magnet machines are used for MRL and high-speed lifts; geared machines suit low-rise and freight. A VVVF inverter with encoder feedback controls speed, giving ±1 mm floor levelling and smooth S-curve acceleration.

Engineering overview

The traction machine and its inverter set ride quality, energy consumption and shaft layout in one decision. Gearless permanent-magnet synchronous machines run 1:1 or 2:1, need no gearbox oil, and are compact enough for machine-room-less shafts; geared worm or helical machines remain economical for low-rise and freight duty where machine-room space exists.

Liftech Global can work on and supply machines and drive electronics across the Monarch, Torin Drive, Monadrive, Fujidrive and Ziehl-Abegg ranges — with sheave diameter, groove profile, brake voltage and encoder type matched to the existing rope size and controller before anything ships.

Drives are closed-loop VVVF with sin/cos or endat absolute encoders, giving ±1 mm levelling accuracy, S-curve jerk limiting below 1.0 m/s³ and, on regenerative units, 20–40% energy recovery back to the building supply.

Types & variants

Gearless PM synchronous (MRL)
Compact 1:1 or 2:1 machine mounted in the shaft head, 320–2 000 kg, 0.4–2.5 m/s.
Gearless high-capacity
2 000–5 000 kg freight and hospital duty with larger sheave and dual brake discs.
Geared worm machine
Traditional machine-room drive for 0.5–1.0 m/s, robust and serviceable.
Helical geared machine
Higher efficiency than worm gearing for 1.0–1.75 m/s mid-rise.
VVVF closed-loop drive
Integrated or standalone inverter with absolute encoder feedback and ARD interface.
Regenerative drive unit
Feeds braking energy back to the grid, 20–40% consumption saving on busy cars.

Technical specifications

Rated load	320 – 5 000 kg
Rated speed	0.4 – 4.0 m/s
Suspension	1:1 or 2:1 roping
Sheave diameter	240 / 320 / 400 / 520 / 620 mm
Rope / belt	Ø 8 – 13 mm steel rope or coated steel belt
Brake	Twin independent DC coils, 110 V DC typical, with proving switches
Encoder	Sin/cos or EnDat absolute, 2048 ppr and above
Insulation / IP	Class F, IP41 (IP54 optional)
Levelling accuracy	± 1 mm floor stop