Electric Elevators: Types, Ideal Requirements, Applications

What is an Electric Elevator?

Electric elevatrors are the electrically operated devices which are used for lifting up and down, moving load in suitable direction, and lifts in multistoried buildings for facilitating up and down movements of occupants, etc. Therefore, it can be said that an electric elevator is an electrically operated device used for transporting at a fixed place.

Types of Electric Elevators

Based on different parameters, electric elevators may be classified into different categories as follows −

Depending on the type of service:

• Passenger elevators

• Freight elevators – for stores, apartments and hotels, etc.

• Special elevators – for garages, side walk, etc.

• Combination of elevators – combination of passenger and freight

Based on capacity:

• Light duty elevators
• Medium duty elevators
• Heavy duty elevators
• Extra-heavy duty elevators

Based on speed:

• Low speed elevators
• Medium speed elevators
• High speed elevators

Depending on power unit:

• Drum elevators
• Traction elevators

Depending on location of power unit:

• Over mounted elevators
• Under mounted elevators

Based on power supply used:

• Direct current (DC) elevators
• Alternating current (AC) elevators

Based on motor drive:

• Geared elevators
• Gearless elevators

Based on rope drive:

• Half wrap elevator
• Full wrap elevator

Based on control system:

• Semi-magnetic type elevator
• Variable voltage type elevator

Based on the method of balancing the load:

• Counter balanced type elevators
• Compensated type elevators

Based on the method of operating the control:

• Semi-magnetic type elevators
• Full-magnetic type elevators

Based on the principle of control:

• Rheostatic controlled elevator
• Variable voltage controlled elevator

Based on the velocity ratio between motor and the car:

• Direct drive elevators
• 2:1 reduction elevators
• Multi-reduction elevators

Based on the method of operation:

• Manually operated elevators
• Push button operated elevators
• Signal operated elevators
• Dual elevators

Ideal Requirements of Elevators

The ideal requirements of an elevator are listed below −

• Size of Elevator Car – The elevator car should have suitable size. The size of the car is determined either from the number of passengers to be carried or by limitations in the building design. In actual practice, it is to allow a space of 2 ft.2 per person.

• Speed of Elevator – The ideal electric elevator should have different suitable speeds for different purposes. The measure of the speed of an elevator car is the number of feet that the car will travel during the period of one minute. For example, for a passenger elevator, the speed is 100–150 ft./minute in private residence, 100–350 ft./min. in hotels and apartment houses, 100–300 ft./min. in department stores, 250–800 ft./min. in office buildings, etc.

• Location of Elevator Machine – The location of the elevator machine should be at a suitable place. Mostly, the elevator machine is installed in a room called the pent house which is located at the top of the building. In some exceptional elevator cars, the machine is installed in the basement, in actual practice it is objectionable because it needs longer hoist cables.

• Motor Drive – The motor drive used in elevators should have smooth working, easy control and reliable operation.

• Shape of Elevator Car – The best shape for an elevator car is the one having a wide front and shallow depth. The wide front provides sufficient door opening and hence facilitating quick transfer of passengers at floor level.

Applications of Elevators

The electric elevators are widely used for lifting up and down different types of load −

• In apartments of multistoried buildings
• In hotels and stores, etc. for passengers and goods
• For side-walks and garages
• In tractions
• In mines for lifting and transporting materials and workers, etc.

Conclusion

From the above discussion, it is clear that the function of elevators is to transport at a fixed place. Also, there are many types electric elevators used according to the need, situation, and purpose. Electric elevators these days are used in almost every other building such in hotels, tall-buildings, malls, garages, offices, etc.