2x8.4m TELESCOPE
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LBT PROJECT
2x8.4m TELESCOPE |
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INDEX:
1. SUPPLY DESCRIPTION.
2. TECHNICAL DATA AND DRAWINGS.
3. SUPPLY RULES.
4. CONSTRUCTION AND ASSEMBLING PROCEDURE.
5. TESTING.
This supply is part of the construction of the LBT Project Telescope, and concerns the construction of the driving units of the two main axes. The supply of driving systems of main axes of the telescope includes the construction and the assembling of nine driving units, one as a spare.
The supply includes one test bench, for the electromechanical performances verifications and setting control equipment of first two units, that shall be carried out by the LBT, in the supplier plant.
Particularly the supply includes, according with the " Statement of Work" of the RFP, the following activities:
1.1 Design review of the driving unit with its adjusting and fixing solutions to the structure, Test Bench, pneumatic plant and electrical connections.
Particularly it shall be foreseen suitable reference surfaces or other solutions to guarantee the alignment of the drive units between them and with the rim gear wheels when mounted on the telescope.
1.2 Developing of all the Workshop Drawings and Part List for the Driving Unit, adjusting and fixing items, Test Bench and pneumatic plant, starting from the assembling drawings included in the Request for Proposal.
The documentation shall be completed with As built drawings, Operations Manual, Maintenance Manual and Acceptance Plan with Test Procedures.
1.3 Preparation of the Manufacturing Plan.
1.4 Preparation of all procedures and methods to execute the critical operations of the manufacturing.
1.5 Manufacturing of all mechanical parts that compose the drive unit, taking care to the high accuracy required particularly to the housing and to the pinion.
The manufacturing includes the spacers under the driving units, the plates that support the drive units of the elevation axis, the adjusting blocks and the pneumatic plant for the brakes supply.
1.6 Buying of all commercial parts being part of the driving unit, with the exception of motors and encoders, that shall be delivered by LBT at the Supplier workshop.
The supply includes the pneumatic brakes, its pneumatic joint, the main block with electro-valves and pressure switches, before and after the electro-valves.
The pipes shall also be provided with their proper length for the final site and also for the pre-erection site in Ansaldo with the pneumatic joint on the azimuth axis for supply the brakes of both axes, including the supports necessary for the fix and the rotating parts of the pneumatic joint ( Dwg. 520a017).
1.7 Test all the items that compose the drive unit.
All the mechanical parts shall be tested and certified on the critical tolerances as described ahead at the point 5.1.
1.8 Painting or surface treatment.
1.9 Assembling of two driving units following the procedure described ahead, including motors, brakes and encoders together with electrical connections until to the electrical box with their connectors, with power separated from signals.
1.10 Construction of one Test Bench, with shaft and other items, on which two driving units must be fixed, aligned and connected one in front of the other.
1.11 Testing of the first two drive units on the Test Bench of all the performances described in the point 5.
The tests will be executed from LBTPO, with the supplier assistance.
1.12 Assembling of the remaining seven driving units following the same procedure, including the motors, brake and encoders together with electrical and pneumatic connections.
1.13 Testing of the remaining seven drive units following the Test specifications.
1.14 Packing all the units ready for shipment sea type.
1.15 Transport to Ansaldo with insurance.
1.16 Technical assistance during the fixing and adjusting of the driving units during the start-up phase in Ansaldo, in order to assure the alignment between the pinions of the driving units and the rim gear wheels, with the defined backlash.
2. TECHNICAL DATA AND DRAWINGS.
2.1.Driving system characteristic and brake data
| - Motor QT-13704 for each drive unit | |
| - Peak motor torque | 795 Nm |
| - Brake MWM AFR 0200 for each drive unit | |
| - Brake torque | 1800 Nm |
2.2.Environment conditions
| - Storage temperature | -30 to +50 °C |
| - Operating temperature | -15 to +25 °C |
| - Storage pressure | 500 to 760 Torr |
| - Operating pressure | 500 to 600 Torr |
| - Storage humidity | 5 to 80 % |
| - Operating humidity | 5 to 95 % |
2.3. Drive Unit Technical Data.
The technical specific data that must be verified on the drive unit on the bench, are as follows:
| - Radial pinion backlash with alternate loads 1000 N | < 1 micron |
| - Braking torque | > 1800 Nm |
| - Pinion rotating torque | < 40 Nm |
| - Rotating error of encoder/tachometer shaft T.I.R. | < 80 micron |
| - Temperature transducers accuracy | < 1 °C |
| - Alignment of all pinion of each axis between them and with the rim gear wheels in both directions | < 0,05/1000 mm |
2.4. Drawings.
The following drawings are enclosed together with this specification:
General assembly
Drive System
2.5. Technical Description
The driving units of the telescope of the LBT Project are four for each of the two main axes, plus one as a spare. The driving unit is made of an housing, inside of which there are assembled all the components.
The pinion shaft is supported in front by one double set roller bearings and one spherical bearing both with internal preloaded tapered ring, and on the back side by one roller bearing.
The stator part of the motor is fixed to the housing, and the rotor part is fixed to the shaft through the friction in order to transmit the torque without any backlash.
On the back side are located the pneumatic brake, the encoder, and the pneumatic joint for the brake.
The driving unit is equipped on the back with an electrical box and connector, to which are connected all the wires. In every housing must be inserted three temperature sensors.
The four brakes of each axis are supplied by two electro-valves, one for each axis, with their pipes.
Two lateral windows are foreseen for brush replacement.
The driving units are provided with suitable reference surfaces or other solutions in order to assure on both axis the alignment between every pinion with each other the engagement with the same rim gear wheels.
2.6.Reliability, Maintenance requirements
The useful lifetime of the telescope is expected to exceed 25 years.
The contractor shall take into account of all aspects which could limit lifetime of the supply.
He shall also contain the number of maintenance interventions, supply adequate access for maintenance operations and minimize risks of damage, loss and injury to personnel and the telescope from telescope maintenance operations.
Particularly shall be provided adequate solutions to put the grease NCA 15 KLUBER with suitable holes to avoid pressure into the bearing and seals.
3.SUPPLY RULES.
The construction of the driving units must comply to the following rules:
3.1. Shop Drawings, planning and technical documentation.
This is the first activity to be performed by the Manufacturer and shall be performed according what specified in the "Statement of Work" of RFP.
3.2.Surface protection and painting.
After sand blasting 5 A 2.5, all the surface of the housing, and other great parts, must be protected with Primer (160 micron thickness), before machining.
The paint after machining must be epoxy type (70 micron thickness) on all the outside housing surfaces, and on the outside surface of the front support and the rear cover.
3.3.Packing.
The packing of the drive units must be made of sea type that can be reused at least 3 times.
3.4.General Rules
The supply, if manufactured in Europe, must comply with the 89/392/CEE rules.
4.CONSTRUCTION AND ASSEMBLING PROCEDURE.
See Dwg. 520a016, 520a013, 460a010
4.1.Mounting procedure
The housing must be welded with stabilization before sand blasting and machining.
All the parts must be tested, particularly the welding, painted, and ready for assembling according the following procedure:
4.1.1 First prepare the housing assembled with the front support item 1.
4.1.2 Insert the pinion from left side in the housing, after having mounted the spherical bearing item 29 without the spacer item 3. Insert from right side the roller bearing item 30 on the shaft without the spacer item 4. Push the internal rings of the two bearings toward the pinion with the screws of the flange item 24 and the grub screws on the nut item 26 until the pinion shaft rotates with a small resistant torque and without radial backlash as required.
Measure the distance between the bearing internal rings and the pinion extremity and grind the spacers item 3 and 4 at the measured dimension. Disassemble the two bearings using an hand pump, pumping oil through the two holes on the front surface of the pinion shaft. The bearings must be greased with KLUBER ISOFLEX NCA 15 .
4.1.3 Mount in the housing the two seal item 32 and the seal item 31 with its flange item 44.
Mount on the pinion the spacers item 3 and 4 and the spherical bearing item 29, and insert the pinion in the housing. Mount from the front side the roller bearing item 30.
Fix the two bearings in their position with the flange item 24 and with the nut item 26, after having verified the outer ring of the spherical bearing in its final axial position.
After having measured the flange item 24, the spacer item 9 can be grinded and inserted.
4.1.4 Assemble inside the housing the flange item 6 complete with its seal item 33 and assemble the external flange item 25 on the external support. Insert the safety key item 5. With the screws item 8 fix at the rotation the pinion shaft after having mounted the cap item 47.
4.1.5 Insert the stator item 10 fixing it with the screws item 11 tightened at 25 Nm.
4.1.6 Assemble the motor rotor item 34 on its bushing item 7 and lock it with the screws item 13.
4.1.7 Rotate the housing in the vertical position. Insert on the shaft upper and the guiding sleeve item 12 foreseen to an easy rotor assembling.
4.1.8 Slide down the rotor item 34 inside the housing, holding it with three eye bolts in the three threaded holes on the rear face of the rotor item 34. During the operation take care of the very high attraction between rotor and stator and orient carefully the rotor aligned with the safety key.
4.1.9 Disassemble the guide item 12 , position the closing nut item 14 and lock axially the rotor tightening the 24 fixing grub screws at 15 Nm.
4.1.10 Assemble the motor brushes.
4.1.11 Disassemble the front screws item 8.
4.1.12 Assemble the rear support item 16 with its seal item 36, its spacer item 35, and the roller bearing item 37 without its inner ring. Mount the flange item 23 with its seal item 39. The bearings must be greased with KLUBER ISOFLEX NCA 15 .
4.1.13 Insert the spacer item 15 and mount the inner ring of the roller bearing on the pinion shaft. Mount the assembled rear support in the housing taking care to the holes position for grease lubrication.
Insert the flange item 22 on the shaft fixing them with the screws item 21.
4.1.14 Insert the ring item 27, insert the key item 43 on the shaft and mount the brake item 17. Fix the braking statoric part with the screws item 45 .
The azimuth brakes disks shall have springs around these screws in order to compensate their weight.
4.1.15 Mount on the shaft the spacer item 46 and fix axially the brake on the pinion shaft with the related threaded ring item 18.
4.1.16 Close the housing mounting the closing rear plate item 19, after having adjusted and mounted the proximity item 28.
4.1.17 Mount the encoder item 41, fixing first the stator part and after screw the inside flange related to the rotor. See the Heidenhain assembling instructions.
4.1.18 Mount the air rotating joint item 42 at the end of shaft.
4.1.19 Close the rear side mounting the cover item 20, and in front with the cover item 47.
4.2.Wiring and piping
With reference to the wiring , the supplier shall receive from P.O. the scheme with cables numbering and type of connectors that must supply and assemble on the rear cover. The wiring of the driving unit includes the electrical connections of what follows items:
The power cables of motors shall be connected to the rear electrical box, whereas the signal cables shall be connected to the plug on the rear of the motor.
The cables shall be of sufficient extra length, in order to permit the dismounting of the cap to get inside, without disconnecting the same cables.
The flexible pipe connects the air joint to the block, providing a fork as counter rotation system.
4.3.Protection of surfaces.
It is recommended before the assembling to protect from the oxidation the inside machined surfaces, laying on it a light oil film.
Before the packing, the outside machined surfaces not painted must be protected adequately with a thick grease or from a special product in order to avoid any oxidation during the transport.
5.TESTING.
The contractor shall prepare and submit to the P.O. the Acceptance Test Plan.
5.1. Parts testing.
With reference to the Quality Control of the Supplier, it must include, at least, the following:
On the Housing:
Each pinion, marked with its reference number, must be certified as follows:
Each front cap, marked with its reference number, must be certified as follows:
The outside ring that carries the stator and the one inside that carries the rotor must be certified as follows:
The support of rear roller bearings must be marked and certified as follows:
The fixing plate of the encoder must be marked and certified as follows:
5.2. Test on the first two Driving units on Test Bench.
The test must be done above a suitable testing bench supplied by the manufacturer.
The first two drive unit must be mounted on a special bench (Dwg. 520a018c), after having mounted the joint shaft item 50 without the cover item 47.
The test of driving unit must be done when completed the assembling, verifying and respecting the following data:
| Pinion radial backlash with alternate loads of 1000 N | <1 micron |
| Braking torque | > 1800 Nm. |
| Rotating torque of the shaft | < 40 Nm |
| Rotating error of the rear shaft diameter T.I.R. | < 80 micron |
| Concentricity between encoder centering and shaft | < 40 micron |
| Reference surface for alignment | < 0,05/1000 mm |
| Temperature transducers accuracy | < 1 degree |
| Verification on intervention of brake proximity | |
| Torsional stiff of the test bench shaft included | > 1 E10 Nm/rad |
| Concentricity and parallelism between the two pinion | < 0,02 mm |
| Band width of velocity close loop* | > 30 Hz |
| * verified by LBTPO | |
All the test will be done by LBTPO, that will supply the electrical cabinet with the amplifier, in the supplier plant under the assistance of the supplier that will give the help necessary, until the completion of the tests.
5.3. Test on the remaining seven Driving units.
The test of driving unit must be done when completed the assembling, verifying and respecting the following data:
| Pinion radial backlash with alternate loads of 1000 N | < 1 micron |
| Braking torque | > 1800 Nm. |
| Rotating torque of the shaft | < 40 Nm |
| Rotating error of the rear shaft diameter T.I.R. | < 40 micron |
| Concentricity between encoder centering and shaft | < 40 micron |
| Reference surface for alignment | < 0,05/1000 mm |
| Temperature transducers accuracy | < 1 degree |
| Verification on intervention of the brake proximity | |
The test must be done above a suitable Test Bench supplied by the manufacturer.
Doc_info_start Title: Technical Specification of Driving Systems Document Type: Technical report Source: ADS Srl Issued by: R. Tomelleri Date_of_issue: June-16-98 Revised by: R. Tomelleri Date_of_Revision: December-23-1998 Checked by: Date_of_Check: Accepted by: Date_of_Acceptance: Released by: Date_of_Release: File Type: MS-WORD 7 Local Name: Categories:Telescope Azimuth Platform and Elevation Mounting Sub-Categories:General Telescope Assembly: Technical Documentation Sub-Assembly: Technical Specification of Driving Systems Part Name: CAN designation: 401a002 Revision: h Doc_info_endLast modified by John M. Hill on Monday, January 11, 1999