An elevator is a platform that is used for lifting people up and down in the buildings. Elevators are part of almost all commercial and residential buildings.It is a vertical transport vehicle that efficiently moves people or goods between floor of a building. Elevators are generally power by electric motors that drive traction cables and counter weight with the help of motors.The overall control is done by control system.
Key parts of elevator are:
.One or more cars(metal boxes) that raise up and down.
.Counter weight that balance the car.
.An electric motor that hoist the car up and down,including a braking system.
.A system of strong metal cable and pulley running between the car and the motor.
.various softer system to protect the passengers if cable breaks.
In large building an electronic control system that direct the car to the correct floor using a “elevator algorithm” to ensure large number of people are moved up and down in the quickest, most efficient way. Intelligent system are programmed to carry many more people to the required floor.

Types of Elevator:There are variety of different hoist mechanism are used to lift up an lower elevator cabs. The most familiar type of elevators are discussed below

• Hydraulics Elevator : It is typically used in low-rise application and its components are fluid tank, buffer and piston.
• Traction Elevator: It uses rope that pass over a wheel attached to a motor that sets above the elevator shaft. This elevators are used for mid to high rise application due to their increased speed and maximum traveling heights.
• Passenger Elevator : Passenger elevators is meant to carry people to their desired floor. They are by for the most prominent types of elevator and are electric elevators mainly based of electric motors and control systems.

Parts of Elevator and its functions : Elevator is made by assembling various parts some are visible to the user and some are working in background. Lets take a close look at parts of elevator and its functions.

• Car : cabin is the main part of elevator which is designed for the shipment of people, goods and services. It contain user interface system that is display board and the switches through which user interact with the system.
• Speed Governors : The speed regulating system of elevator is known as speed governor. If the elevator runs more than the speed limit ,the speed governor control the speed .It is usually attached to the bottom of the car and is also known as governor rope.
• Electric motor : It is main element of which the movement of the car is managed, in case elevator faces and serious condition then electric motor help in preventing it and provide smooth functioning of lift.
• Elevator rail : Sliding up and down in the elevator is possible with the proper functioning of the rail.
• Elevator shaft : Car cabin moves in this space depending upon the type of elevator ,the location of the shaft can be varied.
• Doors : Elevator door are meant for entry and exit , it might be manually operated door or automatic operated door.
• Drive Unit : Everything that works under electricity must have a motor attached for the functioning , it contain a motor that drive a lift.
• Display : Electronic display are inside of the car as well as on the outside of the car. It display the current status of the car , switches are implemented on the board to provide instruction to the elevator and to interact with the control system of the elevator.
• Safety Devices : Mechanical devices are attached to the elevator for safety reasons. In case elevator travel downward with a max speed limit, safety device can maintain a safety and secure traveling.

Working Principle : Elevator work on law of conservation of energy. The elevator gives you potential energy when we are going up and it takes energy from us when we are coming down.

The user call the elevator on the required floor by just pressing the switch then elevator receives request and start moving on the requested floor. Appropriate floor control system gets sensor information and control system signals elevator to stop. Elevator stops control system and signals door to open as soon as door opens the people enter in the car .control system signals the door to close and elevator car door closes , user provide input to the control system on which floor they want to go control system receives the request and motor of the elevator start turning and elevator start moving. As soon as the request floor is reached control system gets sensor information and control system signals elevator to stop and control system signals the door to open and the process repeat continue. If there is no request form the user then then the car will be in the idel state and wait for the call from the user.

Power Supply: Power supply of elevator is s complex process and that is regulated by several laws and it must be provided energy from two independent power source. Break the power is permitted only its time of auto recovery, urgent task is to ensure the possibility of lifting equipment work after the termination of main power supply. As soon as the main power supply is lost then UPS (uninterrupted power supply) will provide the immediate and uninterrupted power supply until inverter or generator provides power supply. This will provide the continuous functioning of elevator without any interruption with the help of power backup.

Control System of Elevator: Group control is the brain of elevator control system which decides were the car should go and stop. There can be several group controller in an elevator. One of the group control is the master that deliver the hall calls to the elevator, and other group control are backup. Other functions inside the car e.g. register and canceling of car call , door control and measurement of car loads are handled by the elevator control .

Intelligent elevator components communicate with each other through serial transmission using controller area network (CAN). Typical control software for an elevator include an operating system , task scheduling programs , input ,output and communication program and program for controlling and optimizing the function of the components.

Standby Mode of Elevator: Standby solution power down the elevator equipment when it is not in use, providing substantial energy saving, especially in buildings with period of lower elevator usage. I-cab sensors and software automatically switch to a “sleep mode’ turning of lights, fans, music and display when the car is not in use. The 25% to 80% of the overall energy consumption of the elevator can be saved depending on multiple variable including the employed control system, lightning type, floor display and operating console in each floor and inside the elevator cabin. As soon as the call button is pressed by the user the elevator will wake up from the sleep mode and again start functioning as earlier and if it is again not used for some time then again it will in standby mode.
Elevator can be made energy efficient by using LED cab lights within an elevator car and their adjustment to movement detector are one of the main contributor toward efficient power consumption in a building. LED also emit less heat, resulting less energy needed to maintain the temperature in cab. LED lightning is currently utilized in many new elevators.

Regenerative Drives of Elevator:  When brakes are applied the energy is released from the electric motors in the form of heat. regenerative drives has the ability to recycle energy rather than wasting it as heat. They work by capturing and converting the energy from braking to maintain the elevator speed. Traction elevator uses a counterweight to balance the weight of elevator car and passenger. If counter weight is to heavy or to light it then the elevator will overwork the motor and the braking system. When the elevator is traveling up the car are light or traveling down car are heavy. The elevator applies the brake to maintain their rated speed. Braking is provided by allowing the AC motor to operates as generator , converting mechanical energy to electrical energy which is dispatched as heat by special heat resistor . The regenerative drive captures the energy and channel it back to the building or the city power grid.