How do regenerative drives for lifts work?

Regular lift drives use electricity to power the motor and move the lift. In this process, any excess energy, generated when the lift descends with a load or travels up empty (counterweight heavier), is wasted. This is where regenerative drives come in.

Here’s the basic principle behind regenerative drives for lifts:

Motor Duality

The lift motor can function in two ways – as a motor and a generator. When supplied with electricity, it acts as a motor, propelling the lift. Conversely, when mechanical energy is applied to the motor shaft (during descent or specific situations), it can generate electricity.

Capturing Excess Energy

During downward movement with a load or empty upward travel, the motor acts as a generator. This generates electricity due to the mechanical energy from the descent or the counterweight.

Power Conversion

The regenerative drive has a special inverter circuit that converts the generated electricity, typically DC (Direct Current), into AC (Alternating Current) compatible with the building’s power grid.

Reusing the Energy

The converted AC electricity is then fed back into the building’s power grid. This can be used by the lift itself during upward travel (reducing the amount of incoming electricity needed) or by other electrical loads in the building.

Braking Resistor (Alternative)

In some cases, the building might not be able to utilise the regenerated power immediately. The drive might divert the excess energy to a braking resistor, which converts it into heat that gets dissipated.

By capturing and reusing the energy that would otherwise be wasted, regenerative drives significantly improve the energy efficiency of lifts. This translates to lower operational costs and reduced environmental impact.