Passenger Elevator Safety and Reliability

Summary:Every building that requires a vertical transportation system will need at least one passenger elevator. These are usual...
Every building that requires a vertical transportation system will need at least one passenger elevator. These are usually of 3500-lb capacity or more.
The popular elevator music was first heard on passenger elevators. Originally, it was used as a way to calm down passengers. It quickly became its own genre of music.
Elevators are large engineering systems that consume 2-10% of total building energy. It has been largely forgotten that they are also carbon footprint systems, as their use is a significant part of the overall transportation system in buildings.
One simple way to reduce motor power and energy consumption is through the use of an efficient drive. Modern drives with matrix converters are designed to control acceleration and deceleration at the elevator level, independent of car loading, reducing energy consumption by up to 30%.
Another energy-saving method involves regenerative drives that capture the gravitational potential energy of descent (heavier than counterweight) or ascent (lighter than counterweight) and return it to the electrical system for reuse. This can reduce the elevator’s energy usage significantly, but does not fully address the issue of standby power consumption. A third solution stores the generated energy in supercapacitors before the drive uses it, allowing a very high level of efficiency. This approach has become popular due to recent improvements in drive technology and lowering capacitor prices.
Elevators are often the unsung heroes of a building, but when they're designed properly, they work together like a well-drilled team. This is because passenger elevators have to meet the highest standards of safety and reliability.
Modern elevators use a traction machine or gearless traction machine with an electric motor to move a car on a hoist rope up or down. They can reach speeds of up to 20 m/s (4,000 ft/min). In addition to the motor, they have a brake that will stop the elevator at the floor if there is a power failure.
A service elevator is found in many commercial buildings and can be used by building staff to carry cleaning carts or larger items around the building. These are typically deeper than passenger elevators, and they may be able to accommodate wheelchairs. This type of elevator is also known as a LULA (Lift to Upper Level Apartment). It is the ideal choice for disabled people who need a lift.
Historically, elevators were powered by ropes that passed over a winding drum in the shaft. When the car weighed less than the counterweight, the ropes provided traction to move the elevator. When the car was heavier than the counterweight, the system operated by applying force to a sheave that the motor drove.
In more expensive installations, the elevator car may be supported by pockets in a hoistway wall or machine beams that attach to the cab. This allows a greater range of speed, travel distance, capacities, and aesthetic options than self-support models.
Control systems vary from single-automatic-push-button to two-car collective operation. In the latter, the elevator cab answers calls in one direction and then reverses to answer a second set of calls in the opposite direction. Energy-saving features include a full-car sensor that prevents the elevator from moving until the car is empty. Other innovations include regenerative drives that capture some of the gravitational potential energy of descent of a fully loaded cab or ascent of an empty cab and return it to the elevator's electric motor.
Many parts of elevators can break down due to regular wear and tear. Having routine inspections helps to find these problems before they can cause any issues with the lift. Generally, commercial passenger elevators should be inspected four times per year.
When selecting a service company to perform routine maintenance on your passenger elevators, verify they have experience servicing the specific type of equipment on the premises. Have them provide references from businesses with the same elevator model that yours have.
In addition to examination of the lift car, shaft components, and safety equipment, a professional company should inspect the hoistway as well. This includes the guide rails on which the elevator car and counterweight run; corridor doors, hangers, and door locks; and operating mechanisms and switches. It also includes the hoist pit, which houses the car and counterweight buffers, cable pulley and tensioning devices, and limit switches. The pit should be free of obstructions that could hinder the operation of the elevator.