The design optimization of an overhead crane with a double box girder has been proposed . In this paper the design optimization of double box girder has been done and a comparative study of results of finite element analysis of a crane with 10 ton capacity and 12 m span length. Electric Overhead Travelling (EOT) Crane is one of the essential industrial equipment for material handling job. design optimization of EOT crane thin walled welded box girder subjected to rolling loads. Keywords: Design Optimization, EOT Crane Bridge, Optimal Box Girder, Rolling. ERECTION & MAINTENANCE OF E.O.T. CRANES: GENERAL: An E.O.T. crane stands for Electric Overhead Travelling crane. this is used for handling &.
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Electric Overhead Traveling. (EOT) Cranes come in various types: 1) Single girder cranes - The crane consists of a single bridge girder supported on two end . consideration of the technical offer for the SUPPLY OF EOT CRANES. S. No. section and plan of the crane) indicating clearances, hook approaches. EOT Crane Specification - Download as PDF File .pdf), Text File .txt) or read online. EOT Crane specification.
All gear shafts shall be supported in bearings mounted in the gear boxes. One brake for each drive should be provided. The CT Drive should be with two corner drive and either of the drives should be capable of operating the trolley movement in case of failure of the other drive. S fabricated. The equalizer sheave should be mounted above the trolley floor and should be easily accessible and removable from the trolley floor level. All gear boxes shall be stress relieved and the method of doing so shall be explained in detail in the offer.
The hardness of gears should be at least 2. Adequate radial clearances between the gear box inner surface and outside diameter of the gears shall be ensured and clearance proposed to be provided shall be indicated in the offer.
Drive mechanisms: The drive mechanisms should have provision for two speeds i. Long travel LT drive: All gear boxes shall be of completely enclosed splash lubricated type. The supplier should further ensure that wire ropes are parallel with each other. The following features are required in addition to those specified in relevant standards. Ramshorn hook with swiveling should be suspended from a balancing beam.
The min. All gears should be with machine cut teeth. The sheave grooves should be smooth finished for getting increased rope life. All parts of the LT drive should be located at proper place. They shall be in accordance with IS: Cross travel CT Drive: Gearing system: Only helical gears should be used for all motions.
Gear boxes shall be provided with breather vents. The hoist should have twin motor drive through VVVF drive.
The LT Drive should be with two-motor drive. If anyone motor fails. They should be identical. Two brakes should be provided.
The hook should conform to the latest edition of BS: Bush bearings should not be used at any location. Bridge buffers should have a contact surface of not less than mm diameter. These should be of a modular.
The motors may be either flange-mounted or foot mounted. The acceptable makes will be NBC. Geared or universal couplings should be used between gear box output shaft and intermediate shaft and wheel axle. Lifting hook: Standard shank Ram shorn hook for the hoist should be used. Bottom blocks and pedestal bearings should have independent greasing points. All the brakes shall be provided with fail-safe D. One of the two hoist brakes shall be applied with a time lag of 3 seconds in relation to the first.
All gear boxes should have drip pans to avoid oil falling on shop floor. Pin Bush coupling should not be used. Disc brakes of reputed make. Buffers should be rigidly bolted in place.
All gears and bearings enclosed inside gear boxes should be splash lubricated. Spring loaded or other suitable buffers should be fitted on the four corners of the crane also at the four ends of the bridge girders. Ball and roller anti-friction bearings shall be of reputed make. Any other special coupling. Motor shafts should be connected to gear extension shafts through flexible shock absorbing couplings.
For long and cross traverse wheels. Double shoe brakes should be provided for each drive. These details should be repeated. Power disconnecting switch on the crane bridge walk way.
Double step push buttons on Telemechanique make pendent and wireless remote control. Earth wire on crane portion. A lubricating chart should be provided in the manual. Protective Switch gears. Copper shrouded down shop leads DSL. Drag link cable system of reputed make like IGUS. Motor control panels. Shrouded bus bar copper conductor along with Isolator switch at the ground level.
Socket outlets. CT motion cables. The control pendent should have separate movement in CT direction independently from trolley. Squirrel cage motors with variable frequency drive for all LT. Electrical equipment shall be adequately rated to permit simultaneous operation of any combination of motions of the crane for its duty service.
Limit Switches. The scope of supply relating to electrical requirements should include the following. Indicating lamps. AC variable frequency controls.
All accessories and auxiliary electrical equipment including drive motors. All crane motors shall be totally enclosed. Pendant shall be moving type and the movement of pendant will be independent of trolley via a separate track along girder length. All motors should preferably be with class 'F' insulation and the maximum permissible temperature shall be limited to class B.
The conductors shall be supported by way of a single piece molding. On all the motions. Pendant push button control for long travel. Crane controls: The following crane controls should be provided.
Specifications for shrouded bus bar conductor: The shrouded bus bar conductor shall conform to the following: Power supply conditions: Sushi Engg. The pull out torque of the motors at rated voltage and frequency should be not less than 2. Two sets of current collectors should be used.
Necessary flexible multi core cable with sufficient length shall be supplied to enable the crane to be operated from floor level. All the motors offered should be suitable for heavy. Lighting fixtures shall be metal halide lamps W x 4 nos. All sundry erection material required for installation and connecting up of electrical equipment with cable laying and fixing accessories shall be included in the price of the crane.
The conductor shall be in minimum of 4 metres length to be jointed with molded joint of the same material. The current collector arm should be aluminum die cast. The limit switch shall act in the event of over hoisting and over lowering. Limit switches and locks: The pendant control shall be capable of withstanding rough handling without being damaged. Two limit switches shall be provided for proper back up protection. The wireless remote control transmitter should be impact resistant.
Telmechnique and Cutler Hammer make. Along with the push button pendant. All contactors shall be of ABB. Circuit protective switch gear: All contactors shall be of AC 4 Class of duty with rating sufficiently higher than the full load current of the respective motors at the specified duty cycle. The directional contactors of all motions shall be suitably interlocked for correct sequence of operation.
CT and LT shall be used by using independent variable voltage.
Independent AC variable frequency control for hoist. The cover shall be firmly secured. The contactors shall have high contact reliability.
Gourp Schneider. Push button operated contactor shall be provided for circuit protection of the crane. The tenderer shall submit necessary technical details of the offered model. CT and hoist motions.
The pendant should be Telemechanique make and the push buttons should be of double step type. AC variable frequency controls: Each control circuit branch to every contactor panel shall be provided with facility for isolation and protection against short circuits and sustained high overloads by means of appropriately rated miniature circuit breaker.
Wireless remote control should have two transmitters and one receiver. All hoist motions shall be provided with limit switches to prevent crane from over hoisting and over lowering. Selector switch on pendant for pendant operation or remote control operation. Brake release should be dependent on motor torque.
Terminal blocks shall be of robust and of such construction as to preclude possibility of cable connections getting loose during vibration on crane.
Single core. Power terminals blocks shall be separated from each other by means of replaceable insulated spacers. All power and auxiliary contactors shall be mounted in sheet steel cubical with lockable hinged doors. The bottom most row of the equipment mounted inside the panel except terminals strips shall be at least mm above the panel bottom cover to facilitate inspection and repairs.
All Limit switches for hoist cross and long travel motions shall be supplied. Control panel IP 55 class protection: Meghashyam, S. Girivardhan Naidu and N. IV May- Jun.
Patel, Dr. Bhatt, Harshad K. Brown, Jr. Related Papers. By Parag Gupta. Download pdf. Remember me on this computer. Enter the email address you signed up with and we'll email you a reset link. Need an account?
Power terminals blocks shall be separated from each other by means of replaceable insulated spacers. Terminal block shall have adequate clearance to avoid tracking. All equipments inside the panel shall have permanent identification labels in accordance with circuit diagram as also the power and control terminals. Terminal blocks shall be of robust and of such construction as to preclude possibility of cable connections getting loose during vibration on crane.
Sheet steel used for fabrication of panels shall have a minimum thickness of 2. Panels shall be mounted such that bottom of panel is at least mm above the floor. Contactor panels shall be well braced to the crane structure and each panel shall be provided with adequate number of lifting lugs.
Cabling work: a. All wiring for power control circuit shall be carried out with 1. Minimum size of cables shall be 4 mm2 for power and 2. All cables shall be systematically laid on G.
All cables shall be of reputed make and approved ISI brands. CT cables of the crane shall run on cable drag chain. Identification of circuit components: Labels of permanent nature shall be provided on supports of all switches, fuses, contactors, relays etc. All panels, controllers etc. All power control cables and other cables shall be ferruled at both ends as per cable numbers indicated in the suppliers drawing.
All equipment terminals shall also to be marked likewise.
Earthing of crane: Earthing to the crane shall be effected through track rails and crane structure. As such, all the electrical equipments mounted on crane shall be connected to the crane structure by means of earthing links.
Equipments fed by flexible cables shall be earthed by means of spare core provided in the flexible cable. Two numbers of fluorescent lamps of suitable rating shall be provided below the crane girder for lighting purpose during crane operation.
However, the downloadr or his authorized representative is free to institute any further checks, if he so desires. All electrical and mechanical equipment shall be tested in accordance with the appropriate Indian Standard at either the crane makers or equipment manufacturers works and test certificates provided if required by the downloadr or his representative.
The following points should be noted during erection and commissioning of the crane. The contractor shall arrange erection and commissioning of the cranes. Adequate number of teams of technical experts will be made available so that erection and commissioning delays are eliminated.
Such personnel will be required to be present immediately as soon as we call upon for erection after receipt of crane at our site and site preparedness.
The following items of work shall be performed by the Contractor. Installing of the crane structure and associated machinery in position. Complete fitting and wiring of all electrical items. Fixing of down shop leads. Commissioning of the equipment. The crane performance shall be demonstrated after successful commissioning. The following will be provided free of cost at the site of work. Test loads with slings and tackles for performing the load tests. The supplier shall transport major crane equipment in assembled modules crab assembly, gear box assembly etc.
Tests on downloadrs Premises: 1.
The contractor shall carry out the start up and trial operation tests commissioning test on receipt of authorization from the downloadr. In addition to tests indicated in IS: latest , the following shall also be carried out: i. The earthing of the crane and control equipment, to be tested as per Indian Electricity Rules.
Inching control and speed as specified in table There is no skewness in crane during long travel and cross travel motions, presence of vibrations and unusual noise in operation. The trials shall be carried out initially under no load conditions and on satisfactory completion of these, trials shall be repeated for various loads until the full rated load and operating speed range are covered.
During the trial operation, all necessary adjustments shall be made so as to ensure compliance with the operating characteristics of the complete equipment as stipulated in the technical specifications.