Electrical Gear Lift

The lifts with rope traction, also named "traditional", are made from a group car frame-cabin and a counterweight. The action is given through a  geared motor composed from a thriphase asynchronous motor and a reduction group (gear).

The gear is in general a crown and worm gear type. The traction is made through a pulley of proper diameter named " friction pulley "( or traction) on which suspension ropes are laid in proper grooves.

When the lift is stopped to a floor, to avoid the movement of the cabin, an electromagnetic brake type actuates its braking power through shoes that operate on a drum placed on the high speed shaft sit between motor and reduction group.

For these kind of lifts the speed of the cabin is determined exclusively from the gear ratio and from the diameter of the traction sheave.

To avoid shaking acceleration to the start and stop of the cabin, the gears are provided with two speed motors in order to allow a start and a stop to lower speeds in comparison with the speeds with which  the lift works during its travel among the floors.

For particular speed lifts, more than 1 m/s, there is the possibility to drive the gear motor with some electronic apparatus (VVVF) for the regulation of the speed in a gradual way and that guarantee a start and a stop of the cabin very comfortable.

The operation VVVF allow to change both the tension both the frequency of motor supply, limiting also the breakaway currents and reducing the superheating of the windings.
An other advantage is to have an accurate control  of the torque  to the lower turns of rotation.