Simplicity, Innovation Mark Residentiall Lift

2018 - Q2 Print

When the Tabbara residential villa in Lebanon’s Bekaa Valley was built 20 years ago, the multistory structure was designed and built without an internal elevator shaft. Perhaps a lift was considered an unnecessary luxury at the time, but today, the owner suffers with knee problems and has difficulty using the stairs. A lift appeared to be the best solution for his situation, so he contacted Al Maaz Elevators & Electric Co. of Beirut for professional advice.

After examining the structure, Al Maaz engineers offered the Alift system to the owner, taking into consideration several advantages the system offers:

  • Minimal space requirements
  • Fast installation
  • Minimal power consumption
  • Environmentally friendly design

These final two points were enhanced with the installation of solar panels on top of the steel lift structure, integrated with a 2.5 kVA DC to AC inverter with storage batteries and a tie-in allowing excess power to be sent to the electric grid, reducing the building owner’s utility cost.

The first consideration for the lift was the most suitable location, as the framework would be constructed on the outside of the structure but would have to afford access to the interior of the building. After careful examination of the premises, it was decided that the front façade would work best, as the balcony of each floor would provide the needed entry points. While this was the most logical location, it included limitations: a machine room could not be used, and a typical pit was impractical because of the hard, rocky soil at the site. Fortunately, the Alift needs neither a machine room nor room for a deep pit.

The Alift combines attributes from the screw-lift jack and the indirect hydraulic lift, and meets safety requirements for passenger lifts in accordance with EN 81-41 standards. It is housed within a steel framework and has no need for a counterweight. For the Tabbara villa, installation began with the assembly of the steel structure, a one-week process that began on June 12, 2017. The lift was installed over the following three days. The three-stop lift has a load capacity of 300 kg and travels at a speed of 0.16 mps. The Alift installed at the Tabbara villa uses a hollow, permanent-magnet synchronous motor (PMSM) that provides noiseless, vibration-free operation and a comfortable ride. Because of its lack of a counterweight, Alift offers space savings of about 30%.

As homes are not typically supplied with a three-phase electric line, Alift is designed to work on a single-phase 220-V current. The 2.2-kW, high-efficiency motor was paired up with a 4-m2 solar panel mounted atop the steel structure and batteries that allow operation of the lift in the event of a power failure. The online grid inverter means lower energy bills for the homeowner.

Characteristics of the Alift

  • Hollow shaft, permanent-magnet synchronous motor (proprietary, patented design)
  • Rated load: up to 325 kg
  • 150-mm minimum pit depth
  • 2,700-mm minimum headroom
  • Output consumption: 2.2 kW
  • Single-phase electrical circuit
  • Combination screw shaft and indirect (hydraulic-style) lift
  • CE certified in accordance with EN 81-41 standards and third-party tested.

The Alift screw-type elevator is characterized by combining two lift systems: an indirect system such as that used in some hydraulic applications and a screw-and-pinion jack system. By using the patented gearless PMSM mounted on a carbon steel pipe (with the ball nut fixed on the rotor shaft of the motor, and the screw shaft passing through the motor inside the pipe), motor rotation allows the ball nut to turn, making the screw shaft go up or down, depending on rotation direction. The screw shaft has a pulley fixed on the top of it, with ropes attached to the cabin on one end and the base floor on the other, in the manner of a hydraulic/indirect system. As the screw shaft rotates, the cabin rises and descends at twice the speed of the screw shaft.

The gearless PMSM offers high efficiency, and, because the cabin is not connected directly to the screw shaft, the ride is very smooth. The single-phase, 220-V low-speed (less than 250 rpm) motor means no vibration, and the system does not use oil. 🌐