The basic principle.
A counterweight travels on the opposite side of the traction suspension. It offsets the car’s weight and an intended portion of rated load, reducing the imbalance the machine must manage.
The car-side load changes as passengers enter and leave. The counterweight does not continually change its mass to match them, so balance varies between journeys.
Two different journeys.
An empty car and a loaded car can demand different torque in the same direction. Under some load and direction combinations, gravity drives the movement and the motor generates.
Follow the relationship.
- Car sideCar plus its current load.
- Counterweight sideA designed balancing mass.
- MachineControls the remaining imbalance and dynamics.
Connect it to the lift.
Counterweights also have guides and associated mechanical constraints. Balance is not the whole power calculation: acceleration, rotating inertia and losses still matter. Counterweight selection is part of the installation design.
A closer look
The simple two-mass picture omits suspension weight, compensation and other effects. These become relevant when evaluating an actual installation rather than explaining the basic principle.
Check your understanding
Does the counterweight make the car perfectly balanced at every passenger load?
Reveal the explanation
No. A fixed balancing mass offsets only a selected loading condition.