Method and controller for displacing an elevator car of an elevator arrangement for evacuating passengers from the elevator car

Abstract

A method and a controller (19) for displacing an elevator car (3) of an elevator arrangement (1) for evacuating passengers (5) from the elevator car are described. Therein, the elevator arrangement comprises the elevator car being displaceable along an elevator shaft (7), an electric elevator drive motor (11) configured for driving the elevator car along the elevator shaft and a elevator brake (13) configured for braking a motion of the elevator car along the elevator shaft. The method comprises: - short-circuiting the electric elevator drive motor such as to configure the electric elevator drive motor for electro dynamically braking a motion of the elevator car along the elevator shaft, - releasing the elevator brake for enabling a motion of the elevator car along the elevator shaft, - monitoring a position of the elevator car along the elevator shaft, and - upon the position of the elevator car reaching an evacuation landing, activating the elevator brake for stopping the motion of the elevator car along the elevator shaft.

Description

[0001] Method and controller for displacing an elevator car of an elevator arrangement for evacuating passengers from the elevator car

[0002] The present invention relates to a method for displacing an elevator car of an elevator arrangement for evacuating passengers from the elevator car. Furthermore, the invention relates to a controller for implementing or controlling such method and to an elevator arrangement comprising such controller.

[0003] Elevator arrangements generally include at least one elevator car which may be displaced along an elevator shaft between various levels. Therein, a level may correspond to a landing or floor in a building such that passengers and / or goods may be transported with the elevator arrangement between the levels in the building. For such purpose, the elevator arrangement comprises an elevator engine which, in most cases, includes an electric elevator drive motor and which is configured for driving the elevator car along the elevator shaft. Accordingly, during normal operation, an intended motion of the elevator car along the elevator shaft may be controlled by suitably controlling a power supply to the electric elevator drive motor.

[0004] Additionally, the elevator arrangement generally comprises a elevator brake for braking the motion of the elevator car. Such elevator brake may be established in various manners. For example, the elevator brake may be arranged at the elevator engine which is for example coupled with the elevator car via suspension traction means and the elevator brake may be configured for braking a rotation motion of the electric drive motor of the elevator engine, thereby indirectly braking the motion of the elevator car. Alternatively, the elevator brake may be arranged at the elevator car and may be configured for directly braking a motion of the elevator car by for example engaging a elevator brake shoe with a elevator brake rail extending along the elevator shaft. In the context of the present document, the elevator brake is a elevator brake that is controllable by a controller and generally used to stop respectively maintain the elevator car at stillstand, for example at floors or landings. It is to be distinguished from a typically present safety gear that only comes into action case of an emergency situation, specifically to stop the elevator car in a dangerous overspeed situation. During normal operation of the elevator arrangement, a displacement motion of the elevator car is generally controlled via a controlled power supply to the electric elevator drive motor of the elevator engine. Therein, the power supply may be controlled using for example an output stage of a frequency converter and / or inverter. In normal operation, the elevator brake is actuated when the elevator car motion is stopping respectively is stopped, for example when the elevator car is stopped at a floor level for enabling passengers to enter or leave the elevator car. The elevator brake may also be actuated for preventing unintended or even dangerous motions of the elevator car. Therein, for safety reasons, the elevator brake is typically configured such that a generally electrical elevator brake release signal has to be continuously provided in order to open, i.e. release, the elevator brake, whereas, without such electric power supply, the elevator brake is actuated and ultimately stops the motion of the elevator car.

[0005] In case of, e.g., an electricity disruption, i.e. a power failure, not only the elevator engine stops driving the elevator car due to lacking power supply to its electric elevator drive motor but also the elevator brake is immediately actuated, thereby additionally stopping and securing the elevator car at its current position within the elevator shaft. The electricity disruption may, e.g., be a breakdown of fault of a typically public power grid. Further, elevator arrangements generally comprise a variety of safety measures and devices, such as a safety chain with a number of contacts as well as sensors for critical operational parameters, such as the velocity and / or acceleration of the elevator car as well as internal variables and conditions of the elevator arrangement. In case of a malfunctions and / or a hazardous and / or potentially dangerous situation being detected, movement of the elevator car can also be directly stopped by discontinuing the power supply to the elevator drive and actuating the elevator brake.

[0006] In such situation, it may be necessary to enable evacuating passengers from the stuck elevator car. For such evacuation, the elevator car which, upon the occurrence of the electricity disruption, is generally located and stuck at an arbitrary position between adjacent landings or floors, has to be displaced towards e.g. a nearest landing such that the passengers may exit the elevator car. Regarding a situation where evacuation of passengers may be required, reference is in this document largely made to an electricity disruption for exemplary purposes. However, it may equally be done in other situations that may require an evacuation as mentioned.

[0007] There are various approaches and strategies for evacuation procedures, some of which are fully or partially automated and some of which are manual. Not every approach is possible and / or safe in very situation.

[0008] In a fully manual evacuation approach, a technician may manually release the elevator brake for example with a lever in order to thereby let the elevator car move along the elevator shaft based on its imbalance until it reaches a next landing where doors of the elevator car may be opened to evacuate the passengers. Therein, a elevator car velocity needs to be limited by the technician suitably reactivating the elevator brake before excessive elevator car velocities endanger a safe displacement of the elevator car. Accordingly, such approach requires a highly skilled technician to be present directly at the elevator. Accordingly, substantial expenditure of work and travel expenses are generally induced for manually evacuating the elevator car. Furthermore, manually releasing and reactivating the elevator brake may result in a non-uniform, i.e. bumpy, displacement of the elevator car, thereby potentially reducing a comfort for the passengers. While generally being possible and required as final option, it is overall disadvantages in a number of ways as mentioned. It is therefore often tried to avoid such procedure and rely on alternative approaches where technically feasible and safe.

[0009] For example, the elevator arrangement may be provided with an emergency power supply which is configured for at least temporarily providing sufficient electricity for continuing a normal operation of the elevator engine such as to allow automated evacuation by displacing the elevator car to a next floor at which the passengers may leave the elevator car. Such evacuation, however, is only limited to a number of situations such as an electricity disruption, but cannot be used in case of, e.g. a failure in the circuitry, a defective sensor, or the like. Further, a rather powerful auxiliary power supply has to be included in the elevator arrangement and has to be permanently kept a t a sufficient charging state, thereby adding significant complexity and costs to the elevator arrangement. WO 2020 / 127982 Al describes a method in which one or more electric pulses are applied to the elevator brake of the elevator car in order to release the elevator brake. With the elevator brake being released and furthermore assuming that, in most cases, there is an imbalance between a weight of the elevator car including the passengers, on the one side, and a counterweight, on the other side, the elevator car will then start moving along the elevator shaft. However, depending on an actual magnitude of the imbalance, a velocity of such elevator car motion may successively increase and may exceed an allowable limit such that the elevator car velocity generally needs to be controlled by suitably controlling the actuation of the elevator brake. Accordingly, a sophisticated controller may be required for establishing such suitable controlling of the elevator brake. Such controller may need its own electricity supply in order to enable temporarily open the elevator brake by applying electric pulses. Furthermore, the controller may need or may have to be connected to sensor means for detecting a current velocity of the elevator car. Finally, the controller may have to be configured to generate and apply electric pulses to the elevator brake in order to suitably open and close the elevator brake for, on the one hand, enable the displacement of the elevator car to the next floor while, on the other hand, prevent excessive elevator car velocities. Accordingly, the controller required for establishing such evacuation procedure is generally a complex and therefore expensive device, thereby adding to the complexity and costs of the entire elevator arrangement. Further, since a sequence with a number of pulses is typically required, the movement of the elevator car is jerky and uncomfortable. Similarly, EP 3216735 Al describes a pulsed opening of an elevator brake enabling passenger evacuation in which electric pulses of a fixed length are applied for temporarily releasing the elevator brake and letting the elevator car move to a next landing.

[0010] WO 2021 / 136738 Al describes an alternative approach for passenger evacuation in which the electric pulses of variable length are applied to the elevator brake, thereby allowing the elevator brake to be maintained in a plurality of positions ranging between a fully opened and a fully closed position. Thereby, the velocity of the elevator car in an evacuation ride can be controlled. However, such approaches require the provision of a PEBO (Pulsed Elevator brake Opening) device, thereby generally adding costs and complexity to evacuation procedures and equipment. Further, the resulting wear of the elevator brake, in particular the elevator brake pads, is high. Accordingly, there may be a need for an improved method for displacing an elevator car for evacuating passengers which at least partially overcomes some of the above mentioned deficiencies of conventional approaches. Particularly, there may be a need for a method with which passengers may be safely evacuated from an elevator car that can be used in various situations requiring a passenger evacuation, while providing increased comfort for the passengers during the evacuation procedure and / or while requiring at most minor hardware changes at the elevator arrangement. Accordingly, there may be a need for an evacuation method which may be established with low complexity and / or at low costs. Furthermore, there may be a need for a controller implementing or controlling such method and for an elevator arrangement comprising such controller.

[0011] Such needs may be met with the subject-matter of the independent claims. Advantageous embodiments are defined in the dependent claims, described throughout the specification and / or visualised in the figures.

[0012] According to a first aspect of the present invention, a method for displacing an elevator car of an elevator arrangement for evacuating passengers from the elevator car is described. Therein, the elevator arrangement comprises the elevator car being displaceable along an elevator shaft, an electric elevator drive motor configured for driving the elevator car along the elevator shaft and a elevator brake configured for braking a motion of the elevator car along the elevator shaft. The method comprises at least the following steps, possibly but not necessarily in the indicated order:

[0013] - short-circuiting the electric elevator drive motor such as to configure the electric elevator drive motor for electro dynamically braking a motion of the elevator car along the elevator shaft,

[0014] - releasing the elevator brake for enabling a motion of the elevator car along the elevator shaft,

[0015] - monitoring a position of the elevator car along the elevator shaft, and

[0016] - upon the position of the elevator car reaching an evacuation landing, activating the elevator brake for stopping the motion of the elevator car along the elevator shaft.

[0017] According to a second aspect of the invention, a controller for controlling displacing an elevator car of an elevator arrangement for evacuating passengers from the elevator car is described. Therein, the controller is configured implementing and / or controlling the method according to an embodiment of the first aspect of the invention.

[0018] According to a third aspect of the invention, an elevator arrangement is described which comprises an elevator car being displaceable along an elevator shaft, an electric elevator drive motor configured for driving the elevator car along the elevator shaft, a elevator brake configured for braking a motion of the elevator car along the elevator shaft and a controller according to an embodiment of the second aspect of the invention.

[0019] Briefly summarised and without limiting the scope of the invention, basic ideas underlying embodiments of the invention and associated possible advantages will be roughly described as follows:

[0020] As indicated above, evacuating passengers from a stuck elevator car requires displacing the elevator car in a controlled and smooth manner while, preferably, not using complex and expensive evacuation hardware.

[0021] In dependence on the overall situation, execution of the evacuation procedure and in particular displacing the elevator car may be done in a partly or fully automatized manner and in particular without on-site presence of an especially qualified and trained person, such as a technician. However, such person may be present, e.g., for initiating and / or supervising the evacuation procedure and / or, e.g. for explaining the procedure the passengers and calming them down.

[0022] The approach described herein uses the fact that an electric elevator drive motor which is generally configured for driving the elevator car may serve as an electro dynamic elevator brake (EDB) upon windings of the motor being short-circuited. Accordingly, an EDB- function provided by the short-circuited elevator drive motor may be used for effectively braking a motion of the elevator car along the elevator shaft. Thus, the elevator brake may be released during an evacuation procedure without risking that the elevator car then accelerates and moves in an uncontrolled manner. Furthermore, as an EDB effect generally increases upon a rotation of the short-circuited motor being accelerated, the short-circuited elevator drive motor may limit the displacement velocity of the elevator car coupled thereto to a sufficiently low value. In other words, while the elevator car may move along the elevator shaft due to the elevator brake being released during the evacuation procedure, the velocity of the elevator car remains low due to the EDB-effect generated by the short-circuited elevator drive motor. Accordingly, the elevator car motion remains slow and smooth and may therefore be easily stopped upon the elevator car reaching a predefined evacuation landing such as a landing at a closest floor.

[0023] Therein, beneficially, the EDB-effect may be induced using relatively simple means for short-circuiting the elevator drive motor. For example, the elevator drive motor may be short-circuited by closing a simple contactor or by suitably controlling an output stage of a frequency converter. Therein, the contactor or the frequency converter may be devices which are already present in conventional elevator arrangements in order to serve for other purposes. Accordingly, the method proposed herein may be implemented by preferably using hardware which is already included in the elevator arrangement, i.e., no or only few additional hardware needs to be provided and / or developed for realising the evacuation approach with the method described herein, thereby possibly keeping costs and system complexity low.

[0024] The short-circuiting may be a direct short-circuiting, e.g., via semiconductor components or a contactor as discussed further below, generally without further components in between. Alternatively, and also encompassed, one or more elevator brake resistors may be arranged in series with the motor windings for energy dissipation.

[0025] In the following, possible features of embodiments of the invention and associated possible advantages will be described in more detail.

[0026] The method proposed herein is specifically configured for displacing an elevator car during an evacuation procedure in order to bring the elevator car to an evacuation landing at which passengers may leave the elevator car. Specifically, the proposed method may be executed in case of an electricity disruption. Such electricity disruption may for example occur upon a power failure in an electricity network or grid supplying energy to the elevator arrangement.

[0027] It is noted that some amount of imbalance is required for the elevator car and the counterweight to start movement. Such imbalance, however, is typically given. The method may be applied to various types of elevator arrangements as long as the elevator car comprised therein is driven along a displacement path in an elevator shaft using an electric elevator drive motor.

[0028] For example, a frequently used type of elevator arrangement includes at least one elevator car which is displaced using a drive engine being mechanically coupled to the elevator car via suspension traction means (STM). Therein, the drive engine includes an electric elevator drive motor coupled to a traction sheave. The traction sheave suspends and drives the STM upon being rotated by the elevator drive motor. The STM generally includes one or preferably multiple load-bearing belts or ropes. Typically, the STM is mechanically coupled to the elevator car at its one side and is mechanically coupled to a counterweight at its opposite side while being suspended and driven by the drive engine and its traction sheave in an intermediate portion between these opposing sides.

[0029] It is to be noted that the method proposed herein may also be applied to elevator arrangements in which the elevator car is displaced using other techniques as long as there is an electric elevator drive motor which is coupled to the elevator car in a manner in which it may both actively accelerate the elevator car’s motion along the elevator shaft as well as elevator brake the elevator car’s motion.

[0030] The elevator car may have any size, load capacity, shape and / or functionality. The elevator car is configured for accommodating one or preferably multiple passengers and / or goods. Generally, the elevator car comprises one or more car doors which may be opened and closed in a controlled manner in order to open or close access to the elevator car. Typically, the car doors are opened and closed using a door drive motor. An operation of the door drive motor is generally controlled by an elevator controller such that the car doors are opened exclusively when the elevator car is stopped at a landing and the elevator doors are closed as long as the elevator car is not stopped at a landing. Furthermore, the car doors and / or the elevator controller are generally configured for the doors automatically closing upon occurrence of emergency cases such as an electricity disruption. Optionally, there may be an auxiliary power supply for such emergency cases such that the car doors may be reliably closed and re-opened even in cases in which a general power supply to the elevator arrangement is disrupted. Further, the doors can generally be opened fully manually at the landings in an exceptional situation, such as an evacuation situation, using a tool.

[0031] The elevator car is displaceable along the elevator shaft. Typically, the elevator shaft extends in a vertical direction. The elevator shaft defines a drive path for the elevator car. For such purpose, one or more elongate guide rails may extend along the elevator shaft and the elevator car, while being driven by the electric elevator drive motor, may be guided along such guide rails while moving along the elevator shaft.

[0032] The electric elevator drive motor is part of an elevator drive engine and may be any electric motor which is suitably configured and sufficiently powerful for driving the elevator car along the elevator shaft. Without limitation, the elevator drive motor may in particular by a permanent magnet (PM) synchronous or asynchronous machine or a reluctance machine with typically a number of, e.g., three phases. For example, the electric elevator drive motor may be configured for providing power in a range of kilowatts for displacing the elevator car. Typically, such electric motor comprises windings to which an electric voltage may be applied and through which an electric current then flows, and thereby generating strong electromagnetic fields. In most cases, the elevator drive motor is configured for rotating operation and comprises a rotor and a stator which may rotate relatively to each other. The rotation is driven by the electromagnetic fields interacting between both components. A power generated by the motor depends on a magnitude of the electromagnetic fields which itself depends on an electric power supplied to the windings of the drive motor.

[0033] Upon such electric elevator drive motor being short-circuited, it may be interpreted as being switched from a motor operation mode to a generator operation mode. In such generator operation mode, the relative motion between magnetic components of the drive motor and electrically conductive components of the drive motor, i.e., a rotation of the rotor comprising magnets relative to the stator comprising windings, or vice versa, results in electric currents being induced in the electrically conductive components. These electric currents may be induced as electric eddy currents and / or as electric currents through any type of electricity consumers. An energy comprised in such electric currents may either be dissipated or may be used, i.e. for example recuperated, for other purposes. Accordingly, upon being short-circuited and therefore being in its generator operation mode, the electric elevator drive motor may serve as an efficient electro dynamic elevator brake. Therein, kinetic energy of the moving elevator car coupled to such short-circuited drive motor may first be converted into electromagnetic energy which is then inducing an electric current. The electric current is then, in most cases, dissipated such as to generate heat, i.e. thermal energy. Overall, the short-circuited elevator drive motor may efficiently decelerate and / or limit the velocity of the moving elevator car.

[0034] Furthermore, such decelerating effect generally depends on a velocity of the elevator car. This results from the fact that, the faster the elevator car moves along the elevator shaft, the faster the electric elevator drive motor is rotated and, as a result, the stronger are the electromagnetic fields or field variations and the resulting electric currents induced in the drive motor, such that, finally, more energy is dissipated. Accordingly, the electric elevator drive motor being short-circuited and operating in its generator operation mode induces a decelerating effect onto the elevator car which increases with the velocity of the elevator car. As a result, the motion of the elevator car will come to a balance in which the motion velocity remains constant. Therein, the final constant motion velocity generally depends on a magnitude of the decelerating effect induced by the drive engine and this decelerating effect generally correlates with a configuration of the drive motor, particularly with its power generation capacity, its size and arrangement of magnetic components and electrically conductive components, etc. With electric elevator drive motors typically used in elevator arrangements, final constant motion velocities being generally smaller than 1 m / s, in most cases smaller than 0.5 m / s or smaller than 0.25 m / s, are observed.

[0035] Additionally to the electric elevator drive motor which, during normal operation of the elevator arrangement, serves for controllably accelerating and decelerating a motion of the elevator car, the elevator arrangement comprises one or more elevator brakes. Such elevator brake may also be referred to as elevator brake or elevator car elevator brake. The elevator brake is configured for braking, i.e. decelerating, the motion of the elevator car along the elevator shaft. Generally, the elevator brake is configured for rapidly decelerating and finally stopping the elevator car motion. During normal elevator operation, the elevator brake may for example be actuated upon the elevator car stopping at a landing floor in order to prevent any elevator car motions for example upon passengers entering or leaving the elevator car. During extraordinary elevator operations such as in emergency cases, the elevator brake may rapidly stop any elevator car motion and / or prevent the elevator car from any further displacement.

[0036] Various types of elevator brakes such as friction elevator brakes, mechanically engaging elevator brakes, electromagnetic elevator brakes, etc., may be used in elevator arrangements. For example, a friction elevator brake may comprise braking pads which may be actively pressed against stationary means such as a stationary guide rail. The elevator brakes may be actuated in various manners including electric actuation, hydraulic actuation, pneumatic actuation, etc. For example, in electric actuation, an electric actuator such as a solenoid actuator, may displace friction generating means. The elevator brake is generally designed such that the solenoid actuator must be continuously energized to keep the elevator brake in in a released respectively non-activated state. If the solenoid actuator is no longer energized, the braking pads are pressed against the stationary means by way of springs, thereby activating the elevator brake. Instead of a solenoid actuator, a hydraulic elevator brake comprises a hydraulic actuator with e.g. a hydraulic pump that needs to continuously provide a hydraulic pressure to keep the elevator brake in the released state against the spring force.

[0037] Generally, the elevator brake may be arranged directly at the elevator car or may indirectly interact with the elevator car. For example, the elevator brake may be attached to a housing or frame of the elevator car such that it moves along the elevator shaft together with the elevator car’s motion. In such configuration, the elevator brake may interact with stationary means such as guide rails being fixedly provided along the elevator shaft in order to generate an intended braking effect. Alternatively, the elevator brake may be arranged at a stationary location within the elevator arrangement but may directly or indirectly interact with the moving elevator car. For example, the elevator brake may be configured for decelerating a rotation motion of the elevator drive motor and, as this drive motor is mechanically coupled to the elevator car, thereby decelerate the elevator car motion. For safety reasons, the elevator brake is generally configured as a normally-actuated device. This means that the elevator brake is always actuated unless it is specifically controlled to be deactivated. For such purpose, the elevator brake may be configured such that an electric elevator brake release signal has to be continuously applied to the elevator brake in order to deactivate, i.e. release, the elevator brake respectively keep it in a released state. Accordingly, as a safety feature, the elevator brake will automatically come to its actuated state in which it decelerates and finally prevents any further motion of the elevator car if the elevator brake release signal is not actively provided. For an electromagnetic elevator brake with a solenoid actuator, the elevator brake release signal may be the signal powering the solenoid(s). For a hydraulic elevator brake, a hydraulic pressure respectively force needs to be continuously applied to keep the elevator brake in its released state and the elevator brake release signal may be a signal powering a corresponding hydraulic pump and / or hydraulic vale(s).

[0038] In the evacuation method proposed herein, the elevator brake, which, initially, is in its actuated state before the evacuation procedure is initiated, is actively released in order to thereby enable a motion of the elevator car along the elevator shaft. With such released elevator brake, the elevator car may then accelerate in an upwards or downwards direction along the elevator shaft, depending on a current imbalance between a weight of the elevator car including the passengers, on the one side, and a weight of the counterweight, on the other side.

[0039] Simultaneously with such release of the elevator brake or shortly before or shortly after such release of the elevator brake, the electric elevator drive motor is intentionally short- circuited. Thereby, the above discussed electro dynamically braking effect is induced, thereby braking the motion of the elevator car along the elevator shaft and, particularly, preventing the elevator car for from accelerating to excessive elevator car velocities.

[0040] Accordingly, with the elevator brake being released and, at the same time, the electric elevator drive motor being short-circuited thereby inducing its EDB effect, the elevator car may slowly move along the elevator shaft.

[0041] During such motion, the position of the elevator car within the elevator shaft may be continuously or repeatedly monitored. Various types of position monitoring techniques may be used for such purposes. Upon detecting that the position of the elevator car is reaching an evacuation landing such as for example a closest landing or floor, the elevator brake is activated in order to thereby stop the motion of the elevator car at this evacuation landing. Additionally or alternatively, the elevator arrangement may have dedicated landing devices that are configured to detect that that the elevator car approaches and / or has reached a landing, especially the evacuation landing. Finally, an elevator door of the elevator car as well as a landing door may be opened such that the passengers may leave the elevator car. Such door opening may be done automatically or manually, e.g. by a technician or housekeeper in dependence on the evacuation strategy and situation. In particular in an automized evacuation, the doors may also be opened automatically.

[0042] At least some of the steps of the proposed evacuation method may be established using technical devices. Therein, at least some of the steps of the proposed evacuation method may be executed in a partly or fully automated manner. Optionally, one or more of the steps may be executed manually or with manual help by a technician.

[0043] According to an embodiment, the short-circuiting the electric elevator drive motor is initiated before the elevator brake is released or simultaneously with releasing the elevator brake.

[0044] In other words, before or simultaneously with the elevator brake becoming deactivated such that the elevator car may freely move along the elevator shaft, the electric elevator drive motor is short-circuited. Accordingly, the short-circuited drive motor may provide its EDB functionality directly with a first beginning motion of the elevator car and may therefore effectively prevent the elevator car from becoming excessively fast. Generally, the elevator drive motor is short circuited directly before releasing the elevator brake.

[0045] According to an alternative embodiment, the short-circuiting the electric elevator drive motor is initiated after the elevator brake is released. In any case, the short-circuiting should be initiated at a velocity of the elevator car that allows a safe evacuation and is generally comfortable for the passengers. Further, it is noted that the electric voltage at the motor windings before the short-circuit is initiated increases with the velocity. Foor a high velocity beyond a velocity limit, attempting to establish the short circuit would result in the corresponding circuitry, such as a contactor or semiconductor components, being destroyed. Exemplary velocity limits of the elevator car for initiating the short-circuiting may, e.g., 0.1 m / s, 0.05 m / s, 0.02 m / s or 0.01 m / s. It is noted that permissible velocities depend on the overall design of the elevator arrangement, such as the design and dimensioning of the circuitry, but also, e.g., the suspension of the elevator car and the sheave diameter.

[0046] Expressed differently, the elevator brake may first be released and, subsequently, the elevator drive motor may be short-circuited in order to initiate its EDB functionality. However, in such implementation, elevator care has to be taken to ensure that the elevator drive motor is short-circuited before the elevator car becoming excessively fast as, otherwise, upon short-circuiting the elevator drive motor at excessively high rotation velocities, such short-circuiting may potentially cause damages at the elevator drive motor and / or at other components cooperating therewith such as power supply circuitries of such motor.

[0047] Accordingly, when releasing the elevator brake before short-circuiting the elevator drive motor, the velocity of the then freely accelerating elevator car should be monitored and it should be guaranteed that the elevator drive motor is short-circuited before the elevator car velocity becoming excessively high. As an alternative, the elevator drive motor may be short-circuited immediately after the elevator brake being released, for example within less than 10 s, preferably less than 5 s, less than 2 s or less than 1 s, after releasing the elevator brake, i.e. within a duration after releasing the elevator brake in which the elevator car generally does not accelerate to excessive velocities (wherein such duration generally depends on an actual imbalance between the elevator car and the counterweight resulting in a respective acceleration of the elevator car).

[0048] According to an embodiment, a velocity of the motion of the elevator car along the elevator shaft is monitored and the elevator brake is activated if the velocity exceeds a predetermined velocity limit value.

[0049] In other words, upon the elevator brake being released and the elevator drive motor being short-circuited, the motion of the elevator car generally depends on first forces generated due to an imbalance between the weight of the elevator car and the weight of the counterweight, on the one hand, and counteracting second forces generated due to the EDB functionality effected by the short-circuited elevator drive motor. While the first forces are generally constant and are mainly caused by gravity, the second forces generally depend on a current displacement velocity of the elevator car, this displacement velocity directly correlating with a rotation velocity of the short-circuited elevator drive motor and this rotation velocity then correlating with the EDB decelerating forces caused by the short-circuited elevator drive motor.

[0050] Generally, the elevator drive motor may be configured such that the decelerating second forces due to the EDB functionality sufficiently counteract the accelerating first forces resulting from gravity such that a balanced state is established in which the elevator car is slowly displaced with a sufficiently low velocity being smaller than a predetermined velocity limit value under all operational conditions.

[0051] However, in particular situations that are generally related to defects of the elevator arrangement, the velocity may increase in an undesired and potentially controllable and / or dangerous manner.

[0052] Accordingly, it may be preferable to continuously or repeatedly monitor the elevator car’s velocity and to activate the elevator brake at least temporarily in cases where the predetermined velocity limit value is exceeded. Therein, the predetermined velocity limit value may depend on characteristics of the elevator arrangement and particularly of its elevator drive motor. For example, the predetermined velocity limit value may be at most 0.5 m / s, preferably at most 0.3 m / s, at most 0.2 m / s or at most 0.1 m / s. Other values are, of course, also possible.

[0053] The elevator brake may then be activated continuously to finally stop the elevator car. After successfully stopping the elevator car, the evacuation may in principle be continued in the same manner using the again the method in accordance with the present disclosure. Alternatively, the evacuation is aborted and subsequently continued with another evacuation approach, using, e.g., a manual release of the elevator brake with a lever as mentioned before. Further the elevator brake may be activated only for a short duration to reduce the current velocity of the elevator car to below the predetermined velocity limit value. For example, the elevator brake may be activated periodically, i.e. with activation pulses being repeatedly applied at repetitive or constant time intervals. According to an embodiment, a temperature of the electric elevator drive motor and or thereto connected circuitry, in particular a frequency converter and / or inverter is monitored and the elevator brake is activated if the temperature exceeds a predetermined temperature limit value.

[0054] Expressed differently, a current temperature of the elevator drive motor, particularly of its components such as its windings, its power circuitries and / or its controller, may be continuously or repeatedly monitored. For such purpose, one or more temperature sensors may be foreseen. As a result of the EDB functionality, the temperature of the elevator drive motor and / or the power circuit, or at least of components thereof typically increases during a deceleration action required in the evacuation procedure described herein. However, as excessive temperatures may induce problems or even damages within the elevator arrangement and particularly within its elevator drive motor or circuitry, the elevator brake may be activated as soon as excessive temperature values are detected. Thereby, the velocity of the elevator car and, correlated herewith, of the rotation of the elevator drive motor are decelerated such that subsequent heat generation induced by the EDB functionality is reduced and the temperature in the elevator drive motor may drop again to below the predetermined temperature limit value. In particular components through which the short-circuit current flows are critical in this regard. As further discussed below in more detail, short-circuiting the elevator drive motor may be done by corresponding control of the output stage of a frequency converter and / or inverter, with the short-circuit current flowing through semiconductor components thereof. Such semiconductor components may accordingly be critical in this regard in addition to the windings of the elevator drive monitor and accordingly require temperature monitoring. In other embodiments as also discussed below a contactor is foreseen for short-circuiting the elevator drive motor. In such embodiment, the contactor and in particular its contacts may be critical and require temperature monitoring.

[0055] The predetermined temperature limit value may depend on characteristics of the elevator drive motor. Particularly, the temperature limit value may depend on components and / or materials comprised in the elevator drive motor. For example, the temperature limit value may be at most 90°C, preferably at least 70°C or at least 50°C. Other temperature values are, of course possible as well. According to an embodiment, the short-circuiting the electric elevator drive motor is established by closing a contactor which electrically interconnects opposing ends of windings in the electric elevator drive motor.

[0056] In other words, the short-circuit within the electric elevator drive motor may be generated by establishing a highly electrically conductive connection between opposing ends of windings in the elevator drive motor. Such electrical connection may be implemented using a contactor. The contactor may also be referred to as main contactor or mechanical contact or as gate, air-gap switch, etc. Typically, the contactor comprises a solid mechanical component consisting of a highly electrical conductive material such as metal, particularly copper, aluminium or other low-resistance metal. Such contactor may be a relatively simple electrical and mechanical component. The contactor may be configured for being opened and closed manually. Alternatively, the contactor may be configured for being opened and closed fully-automatically or semi-automatically. For such purpose, the contactor may comprise an actuator for displacing the contactor between an open state and a closed state. The contactor may be mechanically biased towards its open state such that it may be closed only by actively applying a closing force.

[0057] According to an alternative embodiment, the short-circuiting the electric elevator drive motor is established by suitably controlling an output stage of a frequency converter and / or inverter which is configured for providing power supply to the electric elevator drive motor.

[0058] Expressed differently, the elevator drive motor is generally supplied with electric power via a frequency converter. Such frequency converter typically comprises a semiconductor circuitry which is configured for applying electric power at a predetermined AC frequency in order to control the drive motor with regards to its rotational velocity and / or mechanical power output. Therein, the frequency converter comprises an output stage configured for outputting the supplied electric power to the drive motor. This output stage may be used for establishing the electrical short-circuit for the elevator drive motor. In other words, a component which is already present in the elevator arrangement may specifically be used upon implementing the evacuation method proposed herein. In a particular embodiment, the output stage includes, for each phase of the elevator drive motor, a respective first semiconductor component and a respective second semiconductor component, wherein the semiconductor components are in case switchable between a respective switched-on state and an alternative switched-off state. Each phase is connected with a first potential, in particular a high potential, in the switched-on state of the associated first semiconductor and is connected with a second potential, in particular a low potential, in the switched-on state of the associated second semiconductor component. The method may include repeatedly switching between a first shortcut switching state and a second shortcut switching state, wherein in the first shortcut switching state all first semiconductor components are controlled to assume their respective switched-on state and all second semiconductor components are controlled to assume their respective switched-off state, and wherein in the second shortcut switching state all second semiconductor components are controlled to assume their respective switched-on state and all first semiconductor components are controlled to assume their respective switched-off state.

[0059] With other words, all phases respectively their windings are repeatedly connected with the first potential via the first semiconductor components or the second potential via the second semiconductor components in an alternating manner. In regular operation, only the first semiconductor component or the second semiconductor component may be in the switched-on state at the same time. For shortcutting the motor windings, however, all first semiconductor components or alternatively all second semiconductor components may be controlled to be simultaneously in the switched-on state. The shortcutting the motor windings is accordingly done via the first semiconductor components and the second semiconductor components in an alternating manner. In this way, the heat that is generated in the semiconductor components is equally distributed over all first and second semiconductor components, which is favourably regarding the temperature management. Switching between the first and second switching state may be done with a fixed cycle time respectively frequency. Alternatively, however, the temperature of the first and second semiconductor components may be monitored and switching may be done upon the temperature of the switched-on-semiconductor components assumes a switching threshold temperature. Alternatively, however, only the first semiconductor components may be controlled to assume their respective switched-on state while all second semiconductor components are controlled to assume their respective switched-off state, i.e. only the first semiconductor components or only the second semiconductor components are used for short-circuiting the phases. Such embodiment may be used if switching between the first and second semiconductor components is not required for keeping the temperature in a permissible range. Typically, the permissible temperature of the semiconductor components is about 150°C or below.

[0060] According to an embodiment, the elevator brake is configured to being switchable between two actuation states only, wherein, in a first actuated actuation state, the elevator brake generates a maximum braking effect and wherein, in a second released actuation state, the elevator brake generates a minimum braking effect.

[0061] In other words, the elevator brake may be a mechanically relatively simple elevator brake device which may be switched only between a fully activated state and a fully deactivated state but has no intermediate partly activated states. Such elevator brake may also be referred to as “binary” or “on / off” elevator brake. Such elevator brake may be implemented with simple mechanics and / or at low costs while fulfilling the requirements needed for establishing the method proposed herein. The minimum braking effect may be a non-braking or negligible braking

[0062] According to an embodiment, the elevator brake is configured for generating a maximum braking effect upon an electric elevator brake release signal not being applied to the elevator brake and for generating a minimum braking effect upon the elevator brake release signal being applied to the elevator brake. The release signal may be provided by applying electricity provided by an auxiliary power supply.

[0063] Expressed differently, the elevator brake may be switched between a fully activated state and a fully deactivated state by electrically triggering the elevator brake. For such electrical triggering, an electric voltage may be applied to the elevator brake. Typically, the elevator brake may be configured such that, upon applying a triggering voltage as elevator brake release signal, the elevator brake is released whereas, lacking such triggering voltage, the elevator brake is activated. For executing the evacuation method described herein, the triggering voltage may be applied using an auxiliary power supply to allow an evacuation also in case of an energy disruption. Such auxiliary power supply may be for example a battery. Alternatively, the battery may be small enough to be portable and may be elevator carried by a technician upon executing the evacuation procedure. Such auxiliary power supply may have an electric energy storing capacity which is relatively small, i.e. significantly smaller than in a case where a power supply would have to store sufficient energy for temporarily continuing an entire elevator operation. For example, the auxiliary power supply may have an energy storage capacity of less than 3 kWh, less than 1 kWh or even less than 0,3 kWh. In situations where the needed for the evacuation is not an electricity disruption, the required power may be taken from the supply grid like in regular operation.

[0064] According to an embodiment, the method is executed automatically and is controlled by a controller.

[0065] Accordingly, a controller in accordance with the second aspect of the present invention may be configured for implementing and / or controlling the evacuation method proposed herein.

[0066] In other words, all steps of the proposed evacuation method may be implemented in an automated manner using a controller. The controller may comprise or may be connected to one or more internal and / or external components such as controller circuitries, sensors, actuators, data communication devices, etc. For example, the electric elevator drive motor may be short-circuited by automatically closing a contactor using for example an actuator or by suitably controlling the output stage of a frequency converter. The elevator brake may be released in an automated manner for example by triggering it by applying an electric voltage. The position and / or velocity of the elevator car may be monitored automatically using for example sensors or other monitoring devices. The monitoring data may be observed by a monitoring device in an automated manner in order to automatically activate the elevator brake for stopping the motion of the elevator car upon reaching a position of an evacuation landing.

[0067] The controller may be part of an elevator arrangement according to the third aspect of the invention. Alternatively, the controller may be an external device which may be located remotely from the elevator arrangement. For example, the controller may be part of a remote elevator control centre such that the evacuation method may be controlled from such elevator control centre without a technician needing to visit the elevator arrangement to be evacuated.

[0068] It shall be noted that possible features and advantages of embodiments of the invention are described herein partly with respect to an evacuation method and partly with respect to a controller for implementing such method and an elevator arrangement including such controller. One skilled in the art will recognize that the features may be suitably transferred from one embodiment to another and features may be modified, adapted, combined and / or replaced, etc. in order to come to further embodiments of the invention.

[0069] In the following, advantageous embodiments of the invention will be described with reference to the enclosed drawing. However, neither the drawing nor the description shall be interpreted as limiting the invention.

[0070] Fig. 1 shows an elevator arrangement including a controller and being configured for implementing an evacuation method according to an embodiment of the present invention.

[0071] The figure is only schematic and not to scale. Same reference signs refer to same or similar features.

[0072] Fig. 1 shows an elevator arrangement 1 in which an elevator car 3 elevator carrying passengers 5 may be displaced vertically along an elevator shaft 7. Therein, a drive engine 9 displaces the elevator car 3 upon being supplied with energy by a power supply unit 49 including a frequency converter 29 and an output stage 31. The drive engine 9 comprises an electric elevator drive motor 11 which is configured for rotatably driving a traction sheave 33. The traction sheave 33 cooperates with belts serving as suspension traction means 45 and extending throughout the elevator arrangement 1 such as to suspend both the elevator car 3 as well as a counterweight 47. Accordingly, upon electrically energising the elevator drive motor 11, the drive engine 9 displaces the elevator car 3 along the elevator shaft 7 between various landings 17 at different floors 43 of a building. Therein, the elevator car 3 may be guided using guide shoes 39 sliding or rolling along one or more guide rails 37 vertically extending along the elevator shaft 7.

[0073] For safety reasons, the elevator arrangement 1 comprises one or more elevator brakes 13 with which a motion of the elevator car 3 may be decelerated, stopped, or blocked. For example, a elevator brake 13 provided at the drive engine 9 and referred to herein as sheave elevator brake 35 may be configured for decelerating, stopping or blocking a rotation motion of the traction sheave 33 and / or of the elevator drive motor 11 coupled therewith, thereby indirectly affecting the motion of the elevator car 3. Alternatively, or additionally, a elevator brake 13 provided at the elevator car 3 may be configured for decelerating, stopping or blocking a displacement motion of the elevator car 3 directly. For example, a friction elevator brake referred to herein as a rail elevator brake 41 may be arranged at the elevator car 3 at or closed to one of the guide shoes 39 and may be configured for pressing a friction braking pad against a braking surface of the guide rail 37. Generally, the elevator brake 13 is configured for a normally-closed operation. For releasing the elevator brake 13, a corresponding elevator brake release signal has to be continuously provided to the elevator brake, whereas the elevator brake 13 is otherwise closed. In a non-limiting example, the elevator brake 13 may be an electromagnetic elevator brake with a solenoid actuator. The elevator brake 13 is generally designed for both decelerating the elevator car to standstill and to maintain it at standstill without any torque being applied by the drive engine 9 respectively the elevator drive motor 11 under all load conditions.

[0074] In case of a fault, an energy disruption or generally a hazardous situation, the elevator car 3 may be stuck at a location between neighbouring floors 43 due to an operation of the drive engine 9 being stopped and the elevator brake 13 being actuated due to the lack of electricity. Accordingly, passengers 5 within the elevator car 3 may not leave the elevator car 3.

[0075] In order to evacuate the entrapped passengers 5 from the elevator car 3, the elevator arrangement 1 has to be operated or manipulated such as to enable displacing the elevator car 3 towards one of the landings 17 serving as an evacuation landing 15. For such purpose, the method for displacing the elevator car 3 of the elevator arrangement 1 for evacuating passengers 5 from the elevator car 3 described herein includes at least the following steps:

[0076] The elevator brake 13 is intentionally released, i.e. deactivated, for example by applying a elevator brake release signal or by manually opening the elevator brake 13. Thereby, a motion of the elevator car 3 along the elevator shaft 7 is enabled. Accordingly, the elevator car 3 may start moving upwardly or downwardly, depending on an imbalance of a weight of the elevator car 3 with the passengers 5, on the one side, and the counterweight 47, on the other side.

[0077] Simultaneously with or shortly before or shortly after such releasing of the elevator brake 13, the electric elevator drive motor 11 is actively and intentionally short-circuited. Due to such short-circuiting, the elevator drive motor 11 provides an electro dynamically braking (EDB) effect, thereby decelerating the motion of the elevator car 3 along the elevator shaft 7 or at least counteracting an acceleration of the elevator car 3.

[0078] Accordingly, with its EDB effect, the short-circuited elevator drive motor 11 prevents the elevator car 3 from accelerating to excessive velocities. Favourably, all windings of the elevator drive motor 11 are shortcut. As mentioned before, the shortcut may be a direct shortcut of the windings or a shortcut via one or more elevator brake resistor (not shown), e.g., a elevator brake resistor per phase.

[0079] Subsequently, a position of the elevator car 3 is monitored while the elevator car 3 slowly moves along the elevator shaft 7 towards a neighbouring landing 17 potentially serving as the evacuation landing 15.

[0080] Upon reaching the evacuation landing 15, the elevator brake 13 may activated again in order to thereby stop the motion of the elevator car 13 at the evacuation landing 15. An elevator door 53 may then be opened and the passengers 5 may exit the elevator car 3, thereby successfully finalising the evacuation procedure.

[0081] In order to enable short-circuiting the elevator drive motor 11, the latter may be provided with a contactor 25 which is electrically connected to opposing ends of windings of the elevator drive motor 11. Accordingly, by closing this contactor 25 the windings are short- circuited, thereby inducing the required EDB effect. The contactor 25 may be configured such as to be normally-open. Accordingly, the contactor 25 may have to be actively closed by for example actuating it with a closing force. Such closing force may be applied manually by a technician. Alternatively, the closing force may be applied automatically using a device such as a contactor actuator 27.

[0082] Furthermore, during the evacuation procedure, a velocity of the elevator car 3 may have to be monitored. For example, in cases where the elevator brake 13 is released before the elevator drive motor 11 is short-circuited, it should be guaranteed that such shortcircuiting is established before the elevator car 3 accelerates to excessive velocities of for example more than 0.05 m / s in order to prevent damages at components of the elevator arrangement 1 such as particularly its elevator drive motor 11 or other components, such as semiconductor components in the output stage 31 of frequency converter 29 and / or of the contactor 25. Alternatively or additionally, after the elevator brake 13 is released and the elevator drive motor 11 is short-circuited and therefore counteracts an acceleration of the elevator car 3 with its EDB effect, it should be prevented that the elevator car accelerates beyond a predetermined velocity limit value of for example 0.2 m / s in the interest of a safe and comfortable evacuation ride.

[0083] For such purpose, a velocity monitoring device 21 may be provided. Such velocity monitoring device 21 may receive signals from sensors (not shown) provided at the elevator car 3 and / or provided throughout the elevator shaft 7, these signals indicating a current velocity of the elevator car 3. In case this velocity exceeds the predetermined velocity limit value, the elevator brake 13 may be activated in order to decelerate or even stop the elevator car motion.

[0084] Similarly, during the evacuation procedure, a temperature of one or more units, in particular the elevator drive motor 11 and / or the frequency converter 29, may have to be monitored. For this purpose, a temperature monitoring device 23 with one or more temperature sensors may be provided. The temperature in particular of the elevator drive motor 11 as well as the frequency converter 29 and in particular the semiconductor components of its output stage 31 may significantly increase upon the elevator drive motor 11 being short-circuited and serving as EDB. Generally, an energy converted into heat increases with a velocity of the elevator car 3 and / or with the weight imbalance between the elevator car 3 and the counterweight 47. In cases of excessive elevator car velocity and / or excessive weight imbalance, the temperature of the elevator drive motor 11 may tend to become excessively high. In order to prevent any damages, the elevator brake 13 may then temporarily be activated in order to allow a cooling down. In another approach, the elevator brake 13 is in such situation activated and the evacuation with the elevator drive motor serving as EDB is stopped. Evacuation may be continued using another method as mentioned before.

[0085] Preferably, the evacuation method described herein may be implemented or controlled in a partly or fully automated manner. Accordingly, the evacuation procedure may be initiated and / or controlled by a person which does not need to be highly technically skilled. Alternatively, the evacuation procedure may be initiated and / or controlled remotely.

[0086] For implementing such automation, the elevator arrangement 1 may comprise a specific controller 19. For example, the controller 19 may include a control circuitry (not shown) communicating with the elevator brake 13 for triggering opening and closing the elevator brake 13 during the evacuation procedure by selectively providing or not providing a elevator brake release signal. For such purpose, the control circuitry may for example apply a trigger voltage to the elevator brake 13 for suppressing its actuation and thereby release the elevator brake 13. Furthermore, the control circuitry may be configured for triggering the short-circuiting of the electric elevator drive motor 11 during the evacuation procedure. For example, the control circuitry may control the contactor actuator 27 such as to close the contactor 25 and thereby short-circuit the windings of the elevator drive motor 11.

[0087] Alternatively to shortcutting the windings of the elevator drive motor 11 by way of contactor 25, the control circuitry may control the output stage 31 of the frequency converter 29 in a suitable manner such as to establish the short-circuited within the electric elevator drive motor 11 as described before in the general description. Such embodiment having the advantage of avoiding the need for contactor 25.

[0088] Energy to the controller 19 may be provided by an auxiliary power supply 55 including for example a battery. Finally, it should be noted that the term “comprising” does not exclude other elements or steps and the “a” or “an” does not exclude a plurality. Also elements described in association with different embodiments may be combined. It should also be noted that reference signs in the claims should not be construed as limiting the scope of the claims.

Claims

- 27 -Claims:

1. Method for displacing an elevator car (3) of an elevator arrangement (1) for evacuating passengers (5) from the elevator car (3), wherein the elevator arrangement (1) comprises:- the elevator car (3) being displaceable along an elevator shaft (7);- an electric elevator drive motor (11) configured for driving the elevator car (3) along the elevator shaft (7);- a elevator brake (13) configured for braking a motion of the elevator car (3) along the elevator shaft (7); wherein the method comprises:- short-circuiting the electric elevator drive motor (11) such as to configure the electric elevator drive motor (11) for electro dynamically braking a motion of the elevator car (3) along the elevator shaft (7),- releasing the elevator brake (13) for enabling a motion of the elevator car (3) along the elevator shaft (7),- monitoring a position of the elevator car (3) along the elevator shaft (7), and- upon the position of the elevator car (3) reaching an evacuation landing (15), activating the elevator brake (13) for stopping the motion of the elevator car (3) along the elevator shaft (7).

2. Method of claim 1, wherein the short-circuiting the electric elevator drive motor (11) is initiated before the elevator brake (13) is released or simultaneously with releasing the elevator brake (13).

3. Method of claim 1, wherein the short-circuiting the electric elevator drive motor '(11) is initiated after the elevator brake (13) is released.

4. Method of one of the preceding claims, wherein a velocity of the motion of the elevator car (3) along the elevator shaft (7) is monitored and the elevator brake (13) is activated if the velocity exceeds a predeterminedvelocity limit value.

5. Method of one of the preceding claims, wherein a temperature of the electric elevator drive motor (11) and or thereto connected circuitry, in particular a frequency converter (29) and / or inverter is monitored and the elevator brake (13) is activated if the temperature exceeds a predetermined temperature limit value.

6. Method of one of the preceding claims, wherein the short-circuiting the electric elevator drive motor (11) is established by closing a contactor (25) which electrically interconnects opposing ends of windings (51) in the electric elevator drive motor (11).

7. Method of one of claims 1 to 5, wherein the short-circuiting the electric elevator drive motor (11) is established by suitably controlling an output stage (31) of a frequency converter (29) and / or inverter which is configured for providing power supply to the electric elevator drive motor (11).

8. Method according to claim 7, wherein the output stage (31) includes, for each phase of the elevator drive motor (11), a respective first semiconductor component and a respective second semiconductor component, wherein the semiconductor components are in case switchable between a respective switched-on state and an alternative switched-off state, wherein each phase is connected with a first potential in the switched-on state of the associated first semiconductor and is connected with a second potential in the switched- on state of the associated second semiconductor component, wherein the method includes repeatedly switching between a first shortcut switching state and a second shortcut switching state, wherein in the first shortcut switching state all first semiconductor components are controlled to assume their respective switched-on state and all second semiconductor components are controlled to assume their respective switched-off state, and wherein in the second shortcut switching state all second semiconductor components are controlled to assume their respective switched-on state and all first semiconductor components are controlled to assume their respective switched-off state.

9. Method of one of the preceding claims, wherein the elevator brake (13) is configured to being switchable between two actuation states only, wherein, in a first actuated actuation state, the elevator brake (13) generates a maximum braking effect and wherein, in a second released actuation state, the elevator brake (13) generates a minimum braking effect.

10. Method of one of the preceding claims, wherein the elevator brake (13) is configured for generating a maximum braking effect upon an electric elevator brake release signal not being applied to the elevator brake (13) and for generating a minimum braking effect upon the elevator brake release signal being applied to the elevator brake (13).

11. Method of one of the preceding claims, wherein the method is executed automatically and is controlled by a controller (19).

12. Controller (19) for controlling displacing an elevator car (3) of an elevator arrangement (1) for evacuating passengers (5) from the elevator car (3), wherein the controller (19) is configured for at least one of implementing and controlling the method according to one of the preceding claims.

13. Elevator arrangement ( 1 ) comprising :- an elevator car (3) being displaceable along an elevator shaft (7);- an electric elevator drive motor (11) configured for driving the elevator car (3) along the elevator shaft (7);- a elevator brake (13) configured for braking a motion of the elevator car (3) along the elevator shaft (7); and a controller (19) according to claim 12.

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