The machine room-less (MRL) elevator is relative to the machine room (MR) elevator, which is using modern production technology to miniaturize the equipment of machine room as far as possible while maintaining the original performance, move the control cabinets, traction machine, governor, and other parts to top or sides of elevator hoistway, thus the traditional machine room was cancelled, in order to meet the customer’s special requirements for height and roof.
- The advantages of MRL elevator compared to MR elevator
- The advantage of MRL elevator is saving space. You can only make a maintenance platform under the host.
- Since there is no need room, it is a greater benefit to the structure and cost of the building. This allows the architect to have greater flexibility and convenience in design, and giving the designer more freedom, at the same time if canceling the room, for owners, the cost of building a MRL is lower than MR.
- Some special places, which is inconvenient to set up elevator room, such as hotels, hotel affiliated buildings, and podiums.
- Drawbacks of MRL elevator compared to MR elevator
- Noise, vibration and limitations of using
There are two kinds of methods for place MRL elevator: 1st is that the host is placed on the top car; 2nd is the guide wheel is connected through the shaft. No matter which of the above methods is used, the impact of noise is very great because of using steel connection, and the noise must be digested in the well, plus the sound of the brake, and the fan’s voice will be amplified. Therefore, in terms of noise, the MRL elevator is significantly larger than MR elevator. In addition, due to the rigid connection of the host, the resonance phenomenon is inevitably transmitted to the car and the guide rail, and the influence on the car and the guide rail is relatively large. Therefore, the comfort of the MRL elevator is significantly weaker than MR elevator. Due to the impact of these two items, the MRL elevator is not suitable for high speed trapezoids above 1.75/s. In addition, due to the limited supporting force of the shaft wall, the load-bearing capacity of MRL elevators should not be more than 1150kg. Excessive loading capacity imposes excessive load on the shaft wall, and usually the thickness of reinforced concrete is about 200mm, and brick-concrete structure is about 240mm, both of them are not suitable for carrying too large, so below 1.75m/s or 1150kg situation, MRL elevator can be replaced MR elevator, but for large-capacity or high-speed elevators, MR elevator is significantly better than MRL elevator.
- Temperature Influence
The calorific value is relatively large during running of elevator. At the same time, its various electronic components (elevator spare parts) are relatively poor in the ability to withstand high temperatures, now, MRL elevator and MR elevator are used permanent-magnet synchronous gearless driving machine. The temperature of the permanent-magnetic synchronous motor should not be too high; otherwise it is easy to cause the “loss of magnetism” phenomenon.
- Malfunction Repair and Rescue
MRL elevator maintenance and management is not as convenient as MR elevator. The maintenance and commissioning of MRL elevators are more troublesome, because even the best elevators will inevitably fail, however, the MRL elevator is installed on the beam, and the host is in the hoistway. It is very troublesome for the host (motor) broken.
Through the above comparative analysis, MRL elevators and MR elevators are the same in their use, and their safety performance is also the same, but their respective advantages and Drawbacks are different. The owner can choose MRL elevators or MR elevators according to actual needs.