This design utilizes a geared machine, ropes, and counterweights instead of hydraulic equipment. The main guide rails are mounted on each side of the car and an additional pair of counterweight rails is located on one side or at the rear. The geared machine, along with the related drive equipment, is generally located above the hoistway in a penthouse machine room. In some limited situations, it can be located next to the hoistway at a lower landing. This latter arrangement is referred to as a basement traction.
Advantages:
- No risk of oil contamination to the ground.
- Accommodates front and rear openings in any configuration.
- Available for both low and high capacity cars.
- Nearly unlimited floor travel is possible.
- Has greater power efficiency than hydraulic applications.
- Allows significantly higher car speeds than hydraulic designs.
Disadvantages:
- The material cost is substantially higher than that of hydraulic applications.
- There are structural building considerations because the elevator is supported by the top of the hoistway.
- Elevator maintenance cost is generally greater than that of hydraulic elevators.
- Cycle time for securing the material package and installing it is generally longer than that of hydraulic elevators.
Passenger Traction, Low-Rise Elevator Diagram:
Single Opening (F)
(CWT at Side)
Double Opening (F/R)
(CWT at Side)
Single Opening (F)
(CWT at Rear)
Freight Traction, Low-Rise Elevator Diagram:
Single Opening (F)
Double Opening (F/R)