[<< wikibooks] Building Services/Vertical Transportation/Hydraulic Lifts
Hydraulic Lifts
Hydraulic lifts are powered using a hydraulic ram rather than being suspended.  They are generally suitable for low rise buildings.  The lift car is attached to the top of the hydraulic ram.  When the lift goes up, oil is pumped from a tank into the ram, causing it to rise.  When the lift goes down, the oil is allowed to return to the tank via the pressure of the car on top of the ram.  Hydraulic lifts are usually less expensive than traction lifts and they do not require a large machine room.  The machine room is usually located on the same floor as the lowest floor the lift serves.