Uncontrolled Overspeed

The major part of the design and specification of equipment for the arrest or prevention of overspeed, particularly the safety gear/overspeed governor combination, concerns itself with the performance when carrying rated load, or, in the event of upward overspeed, zero load in the car.  In particular, specification is concerned with performance of safety equipment in the face of suspension failure, however unlikely that might be.  This paper sets out to investigate the performance of overspeed protection when there is a partial load in the car, whether with a failed suspension or not, and to discuss the opportunities in this respect provided by the introduction of the so-called rope brake

An In-depth Study on RTT-HC-MTT Relationship for Passenger Demand beyond Elevator Contract Capacity by Simulation

The traditional elevator system design practice is to calculate the round trip time (RTT) and associated parameters of pure incoming traffic during up-peak, followed by real-time computer simulation. Recent studies indicated that the normal traffic is much more complicated, consisting of a mixture of incoming, outgoing and interfloor patterns. The Universal RTT, under such complicated traffic patterns, was analytically developed eight years ago based on the concept of an appropriate origindestination matrix describing the passenger transit probability, and verified by Monte Carlo simulation. That model is based on the assumption that the total number of passengers demanding service within one round trip is limited to the elevator contract capacity, which is in line with the traditional up-peak incoming RTT formula. The idea of extending the consideration to beyond the contract capacity was initiated two years ago. In this article, an in-depth study on such consideration is carried out so that the performance such as RTT, handling capacity (HC) and mean transit time (MTT) etc. under different traffic patterns is evaluated and analyzed with the help of Monte Carlo simulation. This article may help designers optimally size an elevator system during the RTT calculation stage without oversizing it if the prevalent traffic patterns of the building are known

Towards a global traffic control (dispatcher) algorithm - interface prototype design

This paper presents an overview of the design and development of a prototype Global Dispatcher Interface (GDI) for the control of a group of lifts. The role of the dispatcher is to assign passenger calls to the optimal lift in a group, as decided by a dispatcher algorithm. The GDI is independent of the underlying algorithm, which may be distributed remotely, and provides a standard means through which all interactions may occur. To warrant the “Global” appellation the GDI must support any of the currently available, as well as anticipated, call station modes, types and configurations of cars, topology of control equipment and buildings. The design process is a continuation of a recognised Software Development Lifecycle, centred on Use Cases in a UML model, the initiation of which is covered in a previous paper. Significant diagrams from the model are presented and discussed to illustrate the evolution of the prototype design. One of the requirements, resulting from analysis of the Use Cases, identifies that the GDI design must be compatible with a publish-and-subscribe architecture and a RESTful interface is selected for this purpose. Where possible, the prototype design uses open standards with an emphasis on demonstrating aspects that are specific to lift system dispatcher operation, while attempting to demonstrate independence from implementation details such as programming language, network protocols, etc. The Standard Elevator Information Schema is particularly relevant and fulfils these objectives. The operation of the working prototype, in conjunction with simulated lifts and passengers, is presented as a validation of the design

Modernizations in the post-pandemic world

Abstract. Modernization has been a part of the lift industry for a very long time.  There are buildings that are over 100 years old that have been modernized multiple times but continue to use the original direct current machine.  Both societal changes and technical innovations will make the modernizations of the very near future different from the modernizations of the present.The motivations for modernization, the societal changes, and the technical innovations will be reviewed.  The benefits of the next generation modernization will also be explored

The trip function of a lift

This paper deals with the mathematical derivation of the continuous trip function of a lift. This derivation applies not only to a lift but also to any mass inert mechanism that starts moving from standstill, runs up to a maximum speed or rated speed, to continue for some time, and then stops again after deceleration at completion of its trip along a predetermined track. The trip function determines the traveled distance and the (total) travel time in a continuous relationship with time, rated speed, maximum acceleration and jerk. All kinematic cases of the trip function, such as a short trip without reaching the rated speed, are treated with elaboration of the corresponding specific equations for the total traveled time, maximum achieved speed, etc. The results of the continuous trip function are compared to the results of the equations given in the literature (CIBSE Guide D Annex A2), which are based on a simplified model of the trip function. The conclusion is that the equations based on the simplified model are sufficient accurate for the calculation of handling capacity, journey times, etc. of lifts

Dynamic extension for Ideal Kinematics

This paper presents a new set of equations for modelling kinematic profiles using a combination of mathematical and computational techniques. The implementation of these equations will extend the capabilities of the kinematic model to produce asymmetric and dynamic profiles. This will provide a more accurate model for standard lift systems as well as enable the modelling of more complex systems

Analytical RTT Estimation of a 3-D Elevator System by Exact Stop Positions - Extension to Multi-floor and Non-uniform Population Applications

3-dimensional (3-D) elevator systems will be the industrial trend. Traditionally, designers first perform a calculation on traffic analysis to get an overall concept and then go ahead to carry out simulation to obtain details. This tradition is still maintained throughout the world. In one previous article, a “Scanner” approach was adopted to convert a 2-D or 3-D path of scanning to a 1-dimensional line and a sophisticated origin/destination stops matrix was generated to calculate the round trip time (RTT). A probability matrix was generated with an assumption that only one floor was served in one round trip. In a more recent article, by using order statistics, a method to break down a series of repeatable stops in a 3-D system into several series of non-repeatable stops was developed for easy reasoning by designers. Here, a uniform population distribution of all potential stops and a single floor service were assumed. In this article, by following the concept of the most recent article, RTT calculation could be extended to non-uniform population distribution of stops and multi-floor applications which may be the most general approach to calculate the RTT of a truly 3-D elevator system

Report on Seismic Damage of Lifts and Escalators by Large Earthquakes in Japan

The devastating earthquake of Mw9.0, so-called the Great East Japan Earthquake, hit the Tohoku district, north east part of Japan on March 11, 2011.  About 16,000 people died and 2,500 people were missing by the strong motion and tsunami, and the economic damage was estimated about 16.9 trillion yen in addition to the influence by the nuclear accident of Fukushima Daiichi Nuclear Power Plant.  In addition to the main shock, many strong aftershocks occurred in the long term.  After that, strong near-field earthquakes called the Kumamoto Earthquake and the North Osaka Earthquake occurred in 2016 and 2018.  Many lifts and escalators were damaged in these earthquakes as well as building structures, industrial facilities and so on.  Therefore, this paper reports seismic damage of lifts and escalators by large earthquakes in Japan.  At first, changes of the Seismic Design Guideline in Japan are introduced.  Then a summary of the damage regarding the lifts and escalators was provided in order to confirm effectiveness of Seismic Design Guideline and to contribute improvement of the seismic design for forthcoming destructive earthquakes.  The damage is analysed from the viewpoint of causes, the edition of Seismic Design Guideline and so on.  Although the many of the buildings were hit by massive earthquakes, the damage of the lifts and escalators to be designed according to the Seismic Design Guideline was suppressed to certain level, and the effectiveness of the Seismic Design Guideline was confirmed

Study of Energy Efficiency Benchmarking Parameter based on Real Traffic and Energy Data of a high-speed Traction Lift in Hong Kong

A holistic normalization method (So et al 2005, Lam et al 2006) was developed, which can simultaneously assess both drive efficiency and traffic control performance on a real-time basis of a lift system, termed <J/kg-m> measured in the unit, J/kg/m. Since 2012, it has been adopted by the HKSAR Government as an emerging good engineering practice in the Technical Guidelines of the Building Energy Code. A study of the parameter based on pure simulations using artificial traffic patterns and simple energy patterns was conducted (So et al 2018), recommending that a value of 40 J/kg/m could indicate an efficient system. In this article, the study is conducted again based on real passenger demand and real energy profiles on a bank of seven lifts serving a super-high-rise luxurious office building in Hong Kong, with a conclusion that the previous recommendation is still valid, supported by real data. The study includes variation by simulation in traffic control algorithms and the number of lifts of the bank to study the "undersizing effect" with the same passenger demands throughout a typical weekday, from morning to evening

Fundamental study on rope vibration suppression by middle transfer floor using risk information

Lifts are essential for means of vertical transportation. Recently, the lifts installed in the high-rise buildings are long travel, thus the lift ropes are becoming longer. The natural period of the high-rise buildings is longer than that of the conventional buildings. In addition to the lift rope becomes longer, the natural period of the lift ropes become longer. Accordingly, the natural period of the lift ropes gets closer to the natural period of the building.  Consequently, the lift ropes might be hooked to the equipment of wall when the lift ropes vibrate by an external force, such as a strong wind and earthquake. Furthermore, secondary accident such as containment of passengers and lift service stop may occur. In the Great East Japan Earthquake in 2011, 2015 cases of problem such as the catch and the damage of lift ropes have been reported. Operation of lifts after earthquakes are required for the security of the refuge course. Accordingly, the analytical method for comparative evaluation is investigated in this study. Furthermore, method to prevent a catch by vibration reduction of the lift ropes is investigated. In the previous research, it was confirmed that the division of the lift stroke is effective for reducing the response of the rope. When the lift stroke was equally divided. The displacement of the upper lift became larger than that of the other lift.  Accordingly, the effectiveness of the division ratio of lift stroke was examined in this report. We investigated the catching of the lift rope using differential analysis and risk assessment. As the result, the displacement of the upper lift was decreased by the apposite division ratio. The probability of catching rope of the upper lift is reduced. Furthermore, it was confirmed that the risk of the catching rope reduces in probabilistic risk assessment.Lifts are essential for means of vertical transportation. Recently, the lifts installed in the high-rise buildings are long travel, thus the lift ropes are becoming longer. The natural period of the high-rise buildings is longer than that of the conventional buildings[1]. In addition to the lift rope becomes longer, the natural period of the lift ropes become longer. Accordingly, the natural period of the lift ropes gets closer to the natural period of the building.  Consequently, the lift ropes might be hooked to the equipment of wall when the lift ropes vibrate by an external force, such as a strong wind and earthquake. Furthermore, secondary accident such as containment of passengers and lift service stop may occur. In the Great East Japan Earthquake in 2011, 2015 cases of problem such as the catch and the damage of lift ropes have been reported [2]. Operation of lifts after earthquakes are required for the security of the refuge course. Accordingly, the analytical method for comparative evaluation is investigated in this study. Furthermore, method to prevent a catch by vibration reduction of the lift ropes is investigated. In the previous research, it was confirmed that the division of the lift stroke is effective for reducing the response of the rope. When the lift stroke was equally divided. The displacement of the upper lift became larger than that of the other lift.  Accordingly, the effectiveness of the division ratio of lift stroke was examined in this report. We investigated the catching of the lift rope using differential analysis and risk assessment. As the result, the displacement of the upper lift was decreased by the apposite division ratio. The probability of catching rope of the upper lift is reduced. Furthermore, it was confirmed that the risk of the catching rope reduces in probabilistic risk assessment