Introduction To Electrical Engineering Report Topic Elevator Systems.pdf

It is precisely from the increasing demand for elevator use that this report aims to summarize basic information about some types of elevators, including their structure, operating princ

HANOI UNIVERSITY OF SCIENCE AND

TECHNOLOGY SCHOOL OF ELECTRICAL & ELECTRONIC ENGINEERING

-Introduction to Electrical Engineering Report

Topic: Elevator Systems

Supervisor: Nguyễn Trí Cường Student: Nguyễn Hải Phong Student ID: 20222797

Semester 2023.1

Table of Contents

Preface 2

I History of the development of elevators 3

II General structure and classification of elevators 3

1 General structure of elevators 3

2 Safety requirements in elevators 3

3 Classification of some elevators according to the principle of operation 4

III Structure, operating principle, and characteristics of some types of elevators 4

1 Cable-drawn elevator 4

1.1 Structure 4

1.2 Operating principle 5

1.3 Advantages and disadvantages 6

2 Hdraulic elevators 6

2.1 Structure 6

2.2 Operating principle 7

2.3 Advantages and disadvantages 7

3 Vacuum elevators 8

3.1 Structure 8

3.2 Operating principles 8

3.3 Advantages and disadvantages 8

4 Screw elevators 9

4.1 Structure 9

4.2 Operating principles 10

4.3 Advantages and disadvantages 10

IV Applications of elevators 10

V Trends in the development of elevators 11

5.1 Connectivity 11

5.2 Cloud-based predictive maintenance 11

5.3 Interactive touch screen 11

5.4 Smart cable-free elevator 11

5.5 Automatic Vehicle Storage and Retrieval Technology 12

Table of Contents Preface

Throughout the process of development, humans have always sought to develop tools

to facilitate their transportation Among them, we must mention the invention of the elevator, a vehicle that helps people move up and down in a building more conveniently thanks to mechanical systems The idea of the elevator appeared before the Common Era and has been applied and developed by humans to this day The great role of elevators in the lives of people in the modern era cannot be denied when they appear everywhere, from bustling shopping centers to households or on construction sites It is precisely from the increasing demand for elevator use that this report aims to summarize basic information about some types of elevators, including their structure, operating principles, as well as the advantages and disadvantages of each type of elevator By comparing and contrasting, this report will make some assessments about the future development of elevators

I History of the development of elevators

The earliest reference to elevators appeared around 250 years before the Common Era

In the early days, elevators were described as a box running on a hemp rope pulled by hand

or by animals Ancient and medieval elevators used a pulley-based transmission system until the screw-based transmission system was born, marking the most important step in elevator technology since ancient times, leading to the birth of modern passenger elevators

In 1850, the invention of "standing wire control" was announced by Henry Waterman

in New York, USA In 1852, Elisha Graves Otis introduced the safety elevator, a system that prevents the cabin from falling freely when the load cable is removed, at the New York Crystal Palace Ten years after achieving thousands of elevator products, Elisha's children founded a company specializing in elevator manufacturing, marking the era in which elevators were mass-produced and widely used

By the end of the 19th century, with the advent and development of electricity, elevators in this period were integrated with electric motors by German inventor Werner Von Siemens In 1903, this design evolved into an elevator using a traction machine including an electric motor and a gearbox, which was installed on 100 buildings to become common and change the face of the city forever Multi-speed motors have replaced traditional single-speed models, making operation and stopping smooth This

electromagnetic technique has replaced the manual brake opening and closing system and cable transmission system Control buttons and various complex control systems have revolutionized elevators Moreover, elevators are increasingly being applied with automatic control systems to help improve user experience and enhance safety for users

II General structure and classification of elevators

1 General structure of elevators

Elevators typically consist of one cabin that is used to transport passengers or goods In addition, there are drive systems that pull the cabin up and down during the movement Depending on the type of elevator, this drive system will have different components and structures An essential part of an elevator is the safety system These components are used

to control speed and ensure the safety of passengers in the cabin in all cases

2 Safety requirements in elevators

The system will only operate when:

 The cabin will only move when the elevator car door and the pit door are both closed

 The upper and lower limit switches are guaranteed

 Safety is ensured when the rope breaks, the cable slips, or the power is lost

The safety switches in the cabin are operating properly.

Technical requirements:

 Accurate cabin stop: the cabin must stop accurately at the level of the floor to be stopped If the cabin does not stop accurately, it will cause the following

phenomena: difficulty and danger for passengers to enter and exit; unfavorable movement of goods, etc

 Ensure the highest possible working ability and safety

 Acceleration variation in the allowable range: optimal acceleration ensures high productivity, without causing discomfort to passengers

3 Classification of some elevators according to the principle of operation

- Cable-drawn elevator

- Hydraulic elevator

- Vacuum elevator

- Screw elevator

III Structure, operating principle, and characteristics of some types of elevators

1 Cable-drawn elevator

1.1 Structure

 Cabin control unit: The part that controls the

entire operation of the elevator

 Motor: Used to move the cabin with a hoisting

rope

 Load indicator: A device used to determine the

load capacity of the cabin

 Overspeed protection device: A device that

detects overspeed

 Rope of the overspeed protection device:

Connects to the overspeed protection device to

activate the brake

 Brake: Used to stop the cabin when overspeed occurs and the overspeed protection device is activated

Cable tension pulley: Creates the appropriate tension for the cable of the overspeed protection device

 Travel rope: Provides electrical signals as well as the cabin's power

 Cabin: A space used to transport people or goods

 Cabin frame: The frame that supports the elevator cabin

 Cabin hoisting pulley: Hangs the cabin together with the counterweight with a hoisting rope

 Guide rails: To guide the cabin and counterweight to operate vertically

 Guide shoe: Guides the cabin as well as the counterweight along the guide rails

 Hoisting rope: Connects between the cabin and the counterweight to transmit the driving force from the motor to the cabin and the counterweight

 Door transmission system: Opens and closes the door

 Counterweight: A component that balances the mass of the cabin

 Compensating chain: Compensates for the mass of the hoisting rope

 Dampers: A safety device, designed to stop the cabin as well as the counterweight in case of exceeding the limit, reduce vibration when the cabin or counterweight contacts this device

1.2 Operating principle

In order for the elevator cabin to move as required, the cabin lift cable will be connected to a counterweight suspended on the other side of the cabin, through the cable and pulley To ensure weight balance, the elevator can only operate

Operating principle:

 The electric motor connected to the pulley when operating will help the pulley rotate, from which the cable moves to pull the cabin up or down

 The counterweight with the elevator cabin must be heavier than 40% of the weight of the elevator when operating at maximum capacity When ensuring the correct weight will help the elevator operate in the right process and ensure safety Based on the conservation of energy that has been balanced from the counterweight, the elevator does not need much energy when pulling or lowering

Cable-drawn elevator is based on the balance state, like a child's rocking chair, only a small force is needed to lift the elevator up and vice versa, using the force of attraction to pull the elevator down

 In cable-drawn elevator, the cabin and counterweight are designed with additional sliding rails and sliding shoes, helping the elevator to move smoothly, without shaking, and especially to stop the elevator cabin in case of an accident occurs and the elevator must be stopped immediately

1.3 Advantages and disadvantages

 Advantages

- With the principle of using elevator counterweights, cable-drawn elevator can be installed with an unlimited number of floors On the other hand, it does not need to waste too much energy to lift and lower the cabin like other types of elevators

- For the technology of gearless motors, the size of electric motors is smaller and saves space because there is no need to make a machine room, therefore, it brings higher efficiency when applying cable-pulling technology to install in a small-sized house

- Moves faster and has a longer journey than other types of elevators Cable-drawn elevator provides the fastest travel speed in elevator technologies while still maintaining the smoothness for passengers

- Easy to upgrade when redesigning the house to increase or decrease the number of floors

 Disadvantages

- Due to the high speed of movement, if installed in low-rise buildings, the braking system will quickly deteriorate The sudden increase and decrease of speed when stopping the cabin at a short distance will cause discomfort for users

- A pit is required Due to the high speed of movement, Cable-drawn elevator must have a pit to reduce impact for the cabin and counterweight In addition, the elevator with gearbox motor must have a machine room This increases construction costs, and in many cases cannot be implemented due to building height regulations of the house In this respect, Cable-drawn elevator is more expensive to install and maintain than hydraulic and screw elevators

2 Hdraulic elevators

2.1 Structure

1 Oil tank

2 Drive machine

3 Oil pipe

4 Cabin damper

5 Cabin control panel

6 Rail code

7 Floor door

8 Cabin door

9 Cabin

10 Interlocking lock

11 Cabin door opening and

closing mechanism

12 Cabin roof control box

13 Cabin guide rail

14 Elevator call panel at floor

door

15 Rail lubrication oil box

16 Guide rail

17 Hydraulic cylinder, piston

transmission system

2.2 Operating principle

The pump forces oil from the tank into a pipe leading to the cylinders When the valve

is opened, the pressurized fluid will take the easiest path and return to the fluid reservoir But when the valves are closed, the pressurized fluid has nowhere to go except into the cylinder and push the piston to lift the elevator up

To return the oil in the cylinder to the oil tank, the elevator control system will send a signal to the valve The valve is operated by electricity and by an electromagnetic switch When the electromagnetic valve is opened, the fluid collected in the cylinders can flow out

of the fluid reservoir The weight of the cabin and cargo pushing down on the pistons, the fluid in the Piston flows into the reservoir The cabin gradually goes down Stopping the cabin at a lower floor, the control system closes the valve

When the elevator cabin is at the level, the control system will send a signal to the electrical cabinet to gradually turn off the pump No fluid flows into the cylinder, but the fluid that is already in the Piston cannot escape (it cannot flow back through the pump and the valves are still closed) The piston rests on the fluid, and the cabin position is where it is

2.3 Advantages and disadvantages

 Advantages:

- Fast moving speed: Hydraulic elevators have a speed of 0.3 to 0.6 m/s, which is four times faster than the previous speed of 0.15 m/s This speed meets the requirements of convenient and quick travel, while ensuring absolute safety for all family members

- Smooth operation: This is considered to be one of the most outstanding advantages

of hydraulic elevators It operates without noise (the noise level of hydraulic elevators ranges from 40 to 48 dB) Therefore, it does not affect the sleep of people, especially the elderly and children

- Energy saving: Due to its operation based on the force of the piston, hydraulic elevators only consume electricity in the upward direction and almost no electricity consumption in the downward direction Using hydraulic elevators can save 50%

of electricity compared to many other types of elevators on the market

- Diverse designs: When customers choose to install hydraulic elevators at a reputable unit, your elevator will be customized In addition, you can freely choose from the materials of the elevator such as leather, wood, carbon fiber, precious stones, to the shape and architecture of the elevator

 Disadvantages:

- Limitations of travel height: Due to the hydraulic transmission system using the pressure of the oil stream to lift the piston, the ability of the travel height is limited, hydraulic elevators are suitable for a maximum height of 17-25m (about 7 floors)

- Large initial investment: The initial investment cost of a hydraulic elevator can be large The reason is that most hydraulic elevators in Vietnam are still imported, the installation and operation procedures also need to comply with the standards of the manufacturer, so the initial cost will be higher However, in the long run, the process of wear and tear of components, the need to replace components (screws, hoist ropes) of hydraulic elevators will be less, less need to affect the construction renovation

3 Vacuum elevators

3.1 Structure

Vacuum elevators are built in a vertical and transparent cylindrical structure, allowing people inside to easily see outside The round cabin is designed to be coaxial with the elevator wall The elevator is made of aluminum alloy, with a lightweight but strong load-bearing frame that ensures durability The outer shell has a transparent polycarbonate structure like glass, which blocks ultraviolet rays, is fireproof and soundproof, and is 280 times stronger than glass

3.2 Operating principles

The vacuum pump in the elevator is the part that determines the direction of movement

of the cabin, up or down When the pump sucks air in the area above the cabin, the pressure drops, and the elevator moves up When the pressure increases, the elevator will move gently down to the area with lower pressure

In addition, vacuum elevators are also equipped with a safety valve to push the pressure back to normal in case of an emergency This ensures that users can feel safe when using this type of elevator with high safety

3.3 Advantages and disadvantages

 Advantages:

- Fast installation: Vacuum elevator technology makes it quite easy to install the elevator into the house without having to demolish the construction, affecting the overall structure

- Space saving: Vacuum elevators do not require pit and machine room construction, making them a smart choice for renovation or existing projects In addition, although this type of elevator is not yet available in large sizes (maximum load of 280kg), the entire outer surface is transparent, making users feel the space is large enough spacious and comfortable

- Energy saving: Vacuum elevator technology will not consume energy when moving down a building because this type of elevator uses gravity to bring the cabin from the top floor down to the lower floor

- Superior safety: In the event of a sudden power outage, the traditional elevator will stop halfway and remain locked Vacuum elevators are less risky as they can automatically descend to the lowest floor of the building and open the door for the homeowner to exit

 Disadvantages:

- Limited carrying capacity: Vacuum elevator technology is much smaller than traditional elevators (carrying capacity of only 140kg - 280kg with a capacity of

2 - 4 people), even some types of vacuum elevator technology are not enough space to transport people in wheelchairs

- Fewer stops: Vacuum elevators can only serve buildings from 2 to 5 floors This means that high-rise buildings such as companies, universities, apartments, etc cannot use this type of elevator

- High cost of repair and installation: Vacuum elevators on the Vietnamese market are all imported elevators, so they are expensive In addition, there are very few distributors of this type of elevator in Vietnam, which leads to a lack of materials and tools available for repairing and maintaining vacuum elevators

4 Screw elevators

4.1 Structure

 Mechanical and electrical system: This is the main engine of the elevator, it is the main engine that ensures the elevator operates smoothly and determines the operation

of the elevator

 Worm system: Comes with deep gears and screws The structure of the worm system gives the elevator a special highlight The electric motor acts on the lifting device to help the cabin rise and fall gently according to the user's wishes

 Belt system: It is a special structure of the elevator that participates in the movement process when the elevator motor and worm are operating The belt coil creates a smooth circular movement, ensuring that the elevator operates continuously and safely for a long time