Machine-roomless elevators (MRLs) offer several advantages over traditional elevator designs.
MRLs are a type of traction elevators that do not have a machine room on the top of the hoistway. Instead, the traction hoisting machine is located on the top side wall of the hoistway or on the bottom of the hoistway. The motor is installed with a permanent magnet and works with Variable Voltage Variable Frequency drive. Some hoisting machines use gearless synchronous motors instead of conventional induction motors.
MRLs use conventional steel cord rope for the hoisting cables. Some manufacturers use flat steel rope belts to save space. MRL elevators are usually used in low- and mid-rise buildings up to 20 floors.
There are several benefits to using MRLs. They take up less space and use about 40 percent less electricity than other designs. In addition, they use no oil, which eliminates concerns about leakage and contamination. MRLs also produce less heat and have slightly lower operating costs than traditional elevators. Using them can help a building obtain certification for Leadership in Energy and Environment Design from the United States Green Building Council.
MRLs were introduced in the 1990s. They have been used in Europe longer than the United States because building codes overseas have adapted to the new technology and designs faster.
The newer elevator models are replacing traditional geared traction elevators and beginning to supplant higher-rise hydraulic elevators. The gearless MRLs are becoming the fastest-growing segment in the North American elevator industry as people move away from hydraulic elevators toward greener technology. MRLs currently account for about one-third of the elevator market.