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Five years ago, ThyssenKrupp Aufzüge introduced itsmachine-room-less (MRL) unit, Evolution®. The product andconcept has been received in the market and spawned anentire range of special-application units. The classic unitcomes in two options with standard dimensions for ratedloads of 630kg and a capacity of eight passengers or1000kg with a 13-passenger load with or without an addi-tional opposite entrance. These units come with speedsup to 1.6mps and can travel up to 50 meters.

The flexible unit can be adjusted to handle rated loads upto 1800kg with a capacity of 24 passengers with or withoutthe additional opposite entrance. Speeds up to 2.0mpsand travel heights of 60 meters are possible (Figure 1).The exterior unit was designed as an add-on installation.The elevator comes with a rated load of 450kg and is pre-installed in a glass shaft framework which can be added toa building’s exterior. The traffic unit works well in high-traffic

areas, such as train stations or underpasses. This glasselevator is equipped with vandal-resistant features and hasdisability-friendly options, including voice announcements.

The newest and youngest member of the group is thecompact unit which requires a shaft recess of only 300millimeters (Figures 2 and 3). This option is excellentfor special construction problems, such as rocky terrain.The bottom landing door is monitored electronicallywith a buffer support in the shaft recess for mainte-nance work. A collapsible apron is located underneaththe car door and can be mechanically folded up duringnormal operation and folded out during a power outageor a malfunction of the elevator. It safely covers the gapbetween the car floor and building floor in the event ofpassenger rescue.

All of the Evolution MRLs are equipped with the ThyssenMini gearless® drive. c

EVOLUTION® MRL

Figure 1: Elevator withconventionalshaft pit andmachine room

Figure 2: The ThyssenEvolution®classic withoutmachine room

Figure 3: The Thyssen Evolution®compact without machine room,with a headroom height reduced by100 millimeters and a shallow shaftrecess of only 300 millimeters.

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Elevators without a separate machine room were intro-duced to the market in the mid-1990s and, since thattime, the industry has presented a wide variety of deriva-tive concepts. The motivating factor behind most of theassociated development work was to circumvent patentsalready in force. Often this “circuitous route” resulted insolutions that rendered elevator installation and mainte-nance more difficult. Thus the costs that were saved atthe machine room were shifted to the elevator installationfirm. Manufacturers were even willing to forego provensuspension means such as steel wire ropes in the interestof devising novel solutions. But how can one engineer alift that satisfies the architect’s vision – a lift without amachine room – and the elevator installer’s wishes – easeand safety in maintenance?

These considerations culminated in the developmentof the Apollo/ECD concept presented here. Analogiesdrawn from horizontal passenger transportation, i.e., au-tomotive engineering, are used to explain certain details.

A motor vehicle is aready-to-drive unit thatleaves the assembly plantfully operational. Thedrive train and the con-trol electronics are joinedwith the passenger com-partment in a very limitedand closely defined space.Insulation against noiseand vibration enhancesthe ride quality. An at-tempt was made to iden-tify parallel solutions forvertical passenger trans-port in an elevator cab.The cab rests on a framethat serves as a platformand is moved through thehoistway along the guiderails. If the drive unit isintegrated into that frame,then its rubber mountsisolate the cab from vi-brations generated atthe drive and the guiderollers. All the drive tech-nology, including the con-

trols, should also be mounted on this frame, ready forimmediate use. This makes it possible to traverse the

shaft when the doors are being installed. Moreover, thewiring otherwise needed between the controls, frequencyinverter and drive motor can be eliminated.

A further goal in the development of the machine-room-less (MRL) Apollo/ECD lift was to put a new systemon the market, which, as a patented design, does not in-fringe on any existing patents. On the other hand, itdraws upon components that have proven themselvesthroughout many years of service and thus are deemed to

be absolutely reliable. Moreover, the planner

and elevator installerwere to have available aconcept that imposesno constraints in regardto the positioning of themachinery inside thehoistway and the loca-tion of the temporarymachine room. Position-ing the drive and fre-quency converter (withthe integrated hoistwaycontrols) at the cab elimi-nates any influence onhoistway dimensions. Inaddition, the installationpoint for a connection box(with the circuit breakers,computer interface andmanual controls) andthus the siting of thetemporary machine room

can be selected at will. To satisfy today’s high expecta-tions in regard to noise, efficiency and torque reserves, ahighly dynamic, synchronous servo drive was selected forthe Apollo/ECD lift.

ELEVATOR KIT WITH SELF-PROPELLED CABby Theodor Helmle

Figure 1: Vertical hoistway sectionwith ECD and frequency inverter

Figure 2: Connection panel – positionas desired

Figure 3: ECD elevator motor

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In the interest of simplifying and speeding assembly,all the drive-train components – including the motorand frequency converter with integrated hoistway con-trol – are matched precisely one with another so as toform an integrated, harmonized unit. This in turn makesit possible to use plug-type terminators at the travelingcables and at all other cable connectors.Advantages u Mounting the drive motor inside the hoistway is eliminatedsince the motor is delivered pre-installed at the crosshead.u Smallest possible hoistway dimensions, thanks to mount-ing the entire drive system, including the servo drive andfrequency inverter with its integrated control circuitry, ontop of the cab. u Positioning the temporary machine room as desired, atthe head or the foot of the shaft or at any desired floor. u EMC problems are solved because the frequency inverterwith its integrated controls is fully enclosed in a metalhousing, and the cables between the frequency converterand servo drive are extremely short.

Highlights in the Electronics u Frequency converter and controls are merged into asingle unit: Integration for optimized communicationsbetween control and regulation circuitry, matched preciselyto the servo drive. u Decentralized control technology: Parameters are assignedfor the entire system (control and regulation circuits)using a single on-screen menu. Serial communicationsbus to the individual stations. The programming unit canbe connected at the top of the cab, inside the cab or at theswitchgear cabinet.

u Digital hoistway selector: The digital selector design,doing away with the need for additional incrementaltransducers along the hoistway, brings about a consider-able reduction in assembly time. u Fully automated calibration trips: This trip, made to collecthoistway data, is carried out using the programming unit– at the push of a button, so to speak. u Automatic travel curve optimization: Achieved throughideal specification of travel speeds and the accelerationand deceleration phases, in dependency on the distance tobe covered. This makes it possible to achieve the shortestfloor-to-floor travel times. Characteristics Shortening Installation Times

Since assembly work is always costly, the market successof a new concept will depend to a great degree upon theextent to which assembly time can be reduced. This concepteliminates assembling and wiring for the frequency con-verter and integrated hoistway control unit. The controlsare pre-mounted on the crosshead. All the other cableconnections are made with plugs and sockets. In addition,as was mentioned at the outset, the only componentsemployed in the Apollo/ECD are those which have fullyproven their capacities through years of use. Moreover,the assembly loads and their positioning in the hoistwayhave a critical influence on assembly times.

The Apollo/ECD lift offers significant advantages inmany respects. On the one hand, there is the servo drive,which develops a maximum acceleration moment of 1500Nmwith a total weight of just 135 kilograms (including thedrive sheave). On the other hand, this drive is convenientlymounted at the crosshead and not at a poorly accessible pointin the hoistway, such as directly beneath the shaft ceiling.

Figure 5: Frequency inverter with integrated hoistway controls

Figure 4: Reeving with 270° wrap angle

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The advantage of easy assembly is augmented by thefact that the motor need not be aligned since – by virtueof its being bolted to the cab frame – it is positively centeredon the rails. The traveling cables are pre-assembled at thefactory for immediate use and are easily installed usingplugs which are keyed to prevent incorrect connection.Using components, which are always the same and whichare exactly matched one to another, opens the door tousing motor commutation to implement a digital selector.This is attractive due to its simplicity in assembly andcommissioning, which can be done by a single technicianin a brief period of time. Emergency Rescue

Rescuing trapped passengers must always be givenspecial attention when designing MRLs. The Apollo/ECDlift offers several options to meet customer desires andlocal conditions. Basically, the lift can be moved in theinching mode, under reserve battery power, in the directionof the greater load (cab or counterweight) by using a pushbutton to override the braking switch located in the switchgearcabinet. A leveling sensor indicates that the cab hasreached a landing.

Various options are available to augment this basicversion. A mechanical variation is an additional Bowdencable used to release the brakes mechanically; it is locatedbehind the cab control panel. With this, passengers couldalso be given access to the brake release; the brakes wouldthen automatically re-engage when the cab reached alanding, this being triggered with a mechanical actuator.The elevator can be run automatically and electrically, at48VDC, with a supplementary, battery-buffered auxiliarycontroller. This feature is activated by a phase-monitoringdevice in response to a power failure. The supplementarycontroller attempts to move the cab in a default direction.If the moment developed using the back-up battery andspecified by the auxiliary controller is insufficient to dothe job, then the cab will automatically be moved in theopposite direction, powered by an auxiliary generator.The system will in all events be shut down by the levelingsignal at the nearest landing. Energy Use

In contrast to legal requirements or patent law, all therules and laws of physics apply equally to everyone. Thus,it is not physically possible to move a cab weighing 630kilograms at 1.0mps with only 3.2kW of rated power. Ac-cording to the laws of physics, a system such as thiswould have an overall efficiency level of nearly one. Seenmore seriously, there are essentially two opposing ap-proaches to generating a moment. One option is to usegearing featuring a high step-down ratio in conjunctionwith a high-speed motor developing low-rated torque;the other is a gearless direct drive with high torque and

low speed. The formula P = M ω applies in both cases, andthe product of moment x distance is the same.

When comparing this system with direct drives, gearedmotors are distinguished by their smaller size and lowercopper losses. The reason is found in the limited rota-tional thrust (tangential force) of electrical motors. Due tothe high torque levels needed in elevator drives, exceed-ing 1000Nm, direct drives cannot be compact, nor can alightweight design be used in their manufacture. The advan-tages of direct drives can be exploited only where highertravel speeds are specified. In most cases (up to about2mps rated speed), optimized helical gearing and drivemotors with dynamically balanced rotors are of equiva-lent quality and operational utility but represent the morecompact and more economical solution. The great copperlosses in direct drives have to be added to the drive power,and this will have to be taken into account when selectingthe frequency inverter.

A further disadvantage of gearless drives results fromthe rules applicable to elevator technology. Every drivehas to brake mechanically when it is at rest, and thebrakes have to be held open electrically during the entiretrip. A redundant, dual-circuit brake system is prescribedhere. Moreover, the brakes have to be dimensioned sothat either of the brake circuits is able to stop and holdthe lift securely. In gearless direct drives the unavoidableresult is a very large brake system since it has to counteractall the moment present at the drive sheave. The effects of thisdisadvantage are even more acute in the 1:1 gearless appli-cations now coming into use. The brakes’ power consump-tion (when released) is proportional to the braking force.

In drives utilizing gearing, the brakes are downlinefrom the gearbox. The braking moment to be applied isreduced by the step-down gearing, resulting in a smallersystem with lower power consumption.

Marketing The Apollo lift is being marketed in Germany by Leistritz

in the form of a complete construction kit. Distribution inthe remainder of Europe is in the hands of the KleemannCo., while the Edunburgh Co. is responsible for Asia.

Theodor Helmle is head of Business Unit Elevators at alphagetriebebau GmbH.

Technical data

Payload 630 kg, optionally 1000 kg

Rated output 4.9 kW

Velocity 1.2 mps

Acceleration 0.7 mps2

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