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Doc #: 2100 AD 015 0031 Revision: 4m Dec Axis Counterweight Removal,

1 Doc #: 2100 AD Revision: 4m Dec Axis Counterweight Removal, Disassembly, Maintenance, & Reinstallation Procedure Author(s): Matthew John Evatt

2 Contents 1. Contents Revision History Purpose Applicable To Scope Definitions Training Safety Personnel, Equipment and Materials Required Procedure Procedure Review Records References AD DOCX Page 2 of 15

3 Revision History Rev Date Approved Sections Affected Reason for Change Remarks and/or Change Details Name Released M. Evatt Approved by: SigEng Name, ME Title SigEM Name, EL Maint SigSci Name, SciOps Signature 11 February 2016 Tammie Lavoie, Safety Manager Date 2100 AD DOCX Page 3 of 15

4 Purpose The purpose of this document is to capture the procedure for the removal, disassembly, maintenance, reassembly, and reinstallation of the E002 4m Telescope Declination Axis Counterweights. Applicable To This procedure is applicable to the Mayall 4m Declination Axis Counterweight Assemblies. Scope The scope of this procedure encompasses preparation for removal, disassembly, maintenance, reassembly, and reinstallation of the E002 4m Telescope Declination Axis Counterweights. Definitions Training No special procedural training required. On the job knowledge of Mayall dome environment required. Fall protection training required. Lock out tag out training required. Safety 6.1 JHA Form 6.2 Daily Briefing Form 6.3 Kitt Peak Emergency Manual 7. Personnel, Equipment and Materials Required 7.1 Personnel Removal: Four people including one crane operator 7.2 Equipment Two 1 ton (minimum) chain hoists with about 15 feet of lifting travel (Note: bottom of ring to top of center section is 25 feet) Two 12 foot long 1 ton (minimum vertical rating) slings Two 4 foot long 1 ton (minimum vertical rating) slings Two ½ inch shackles One ¾ shackle 2100 AD DOCX Page 4 of 15

5 One 1 ton dynamometer ¾ socket with ½ inch drive (include various extensions just in case) Various Allen wrenches, hex wrenches, sockets, screwdrivers, brass hammers, soft blow mallets, etc. 5 ton dome bridge crane Machine Shop to modify the existing C010 NUT, TRAVEL, DEC AXIS COUNTERWEIGHT. V blocks for supporting the counterweight horizontally on the floor once it is removed from the counterweight tube. 7.3 Materials 8 EA (PER COUNTERWEIGHT) B022 DECLINATION AXIS COUNTERWEIGHT SLIDE DETAIL 8 EA (PER COUNTERWEIGHT) B023 DECLINATION AXIS COUNTERWEIGHT SLIDE SUPPORT DETAIL Chainlife lubricant (Note: Does not contain molybdenum disulfide, so it CAN be used on yellow metal parts like the Dec tube nut inserts we will be installing) Dec Tube Nut Inserts (one per Counterweight assembly) AD DOCX Page 5 of 15

8. Declination Counterweight Removal Procedure Note: Weight of Counterweight Assembly: 1700 lbf Weight of Counterweight including Nut: 1000 lbf (Both weighed during 2015 Summer Shutdown) 8.

6 8. Declination Counterweight Removal Procedure Note: Weight of Counterweight Assembly: 1700 lbf Weight of Counterweight including Nut: 1000 lbf (Both weighed during 2015 Summer Shutdown) 8.1 Rig chain hoists and slings from top ring over counterweights For south counterweights (Figure 1): Rotate telescope down to so the 12 foot slings can be chokered around the top ring. Hang chain hoist from each 12 foot sling and secure to Serrurier truss tube to ensure it cannot fall when moving the telescope. Make sure hoists hang as close to directly over the counterweight assemblies as possible when the telescope is rotated back up to Zenith For north counterweights: Use crane personnel basket to lift and hang 12 foot slings and chain hoists over the counterweights. 8.2 Back off one of the three pusher bolts that help hold the counterweight assemblies in place. One of the pusher bolts must be backed off from each counterweight to allow the counterweight to be pulled out from the telescope For south counterweights (Figure 2): Rotate telescope so personnel can walk out onto ellipse tubes. Fall protection is required for this operation Remove blower hose from PM cooling fan blower to reach pusher bolt (Figure 3) Loosen lock nut on pusher bolt assembly Screw pusher bolt back away from counterweight assembly. 8.3 Move telescope to Zenith. Figure 1. Rigging for South Counterweight Removal Figure 2. Backing Off Lower Pusher Bolts on South Side Counterweights 8.4 Install Dec and RA stay bars to prevent telescope movement when unbalanced. 8.5 Place the Do Not Use placard over control console. 8.6 Lock out telescope drives using Lockout / Tagout procedure AD DOCX Page 6 of 15

8.7 Remove ½ 13 Hex Head Bolts (3/4 Socket) from Counterweight Assembly flange. 8.8 Disconnect all wiring between telescope and Counterweight Assembly. This wiring is Figure 3.

Also, wrap the potentiometer in cardboard to protect the solder joints on top (Figure 4). 8.

7 8.7 Remove ½ 13 Hex Head Bolts (3/4 Socket) from Counterweight Assembly flange. 8.8 Disconnect all wiring between telescope and Counterweight Assembly. This wiring is Figure 3. View of Pusher Bolts from Top after Counterweight Removed all at the top of the Counterweight Assembly. Wrap wiring around motor and tape so it will not get damaged (Figure 4). Also, wrap the potentiometer in cardboard to protect the solder joints on top (Figure 4). 8.9 Install one ½ lifting shackle in the each eyebolt as shown in Figure 4 and run two 4 foot straps between them. Connect one of the 4 foot straps to the hoist hook (with the dynamometer in between) using a ¾ shackle as shown in the figure. The other strap will be used to transfer to the 5 ton crane Remove the bolt from one end of the small corner piece of hand rail above the counterweight to be removed and rotate it up out of the way so the counterweight can be moved between the two corner Serrurier truss members (Figure 5) Begin lifting the counterweight assembly out of the center section with the chain hoist. Make sure it doesn t snag anything as it s coming out. The weight of the counterweight assembly is 1700 lbs. Use the dynamometer to monitory the lifting tension in the hoist. Figure 4. Counterweight Rigged and Protected for Lifting 8.12 When the counterweight assembly is high enough so it can be maneuvered between the corner Serrurier truss members, move the 5 ton crane hook down close to the chain hoist hook. Note: Make sure to watch the locations of the crane cables as they get close to the top ring AD DOCX Page 7 of 15

14 Once the 5 ton crane is carrying the load of the counterweight assembly, lower the chain hoist until it is slack, and then remove the chain hoist hook from the ¾ shackle. 8.

8 8.13 Place the loose 4 foot strap onto the 5 ton crane hook. After that strap is secure, the 5 ton crane hook can be raised slowly to take the weight of the counterweight assembly off of the chain hoist Once the 5 ton crane is carrying the load of the counterweight assembly, lower the chain hoist until it is slack, and then remove the chain hoist hook from the ¾ shackle Maneuver the 5 ton crane hook and counterweight assembly away from the telescope and over the mezzanine floor (near the location where the mirror is placed when it is removed). Place the counterweight assembly Figure 5. Rotate Corner Handrail Piece Out of the Way vertically on cribbing up against the scissors lift taking care not to damage the limit switch on the bottom of the assembly (Figure 6). Secure the counterweight assembly to the scissors lift Remove the straps from the 5 ton hook and stow the 5 ton crane Make sure the counterweight assembly is stable and safe then repeat or proceed to the Declination Counterweight Disassembly Procedure section below. Figure 6. Counterweight Being Set Next to Scissors Lift 2100 AD DOCX Page 8 of 15

9. Declination Counterweight Disassembly, Rework, and Assembly Procedure Note: Refer to the following drawings: 2150 289 E002 Rev F Declination Axis Counterweight Assembly 2150 289 E024 Rev?

9 9. Declination Counterweight Disassembly, Rework, and Assembly Procedure Note: Refer to the following drawings: E002 Rev F Declination Axis Counterweight Assembly E024 Rev? Rework Declination Axis Counterweight Assembly D020 Rev? Declination Axis Counterweight Assembly D021 Rev A Declination Axis Counterweight Counterweight Detail 9.1 Unscrew the top limit switch from the top plate. 9.2 Open j box on top plate and disconnect lower limit switch wiring. 9.3 Disassemble and remove the 90 deg elbow conduit connector from the j box. 9.4 Unscrew the conduit fitting that goes through the top plate from the conduit taking care not to twist the lower limit switch wires. 9.5 Remove the bolts holding the top plate onto the tube. 9.6 Install two shouldered lifting eyes in two 180 degree separated top plate flange holes. 9.7 Connect a 4 foot lifting strap to each of them using a ½ shackle and connect the other ends of the straps to the 5 ton crane hook (Figure 6). 9.8 Lift the top plate assembly with the counterweight attached using the 5 ton crane. It will be necessary to hit the top plate and / or the tube with a hammer to help release the top plate (Figure 7). 9.9 Set up 4x4 cribbing on the floor to set the weight on Move the top plate / weight away from the tube and lower until the bottom of the lead screw is an inch or so above the floor Begin screwing the weight down the lead screw (Figure 8). Ensure that it is very close to the cribbing it will sit on before it comes off the lead screw. Do not drop on foot. This thing weighs 1000 lbf. It s YOOOOGE! Figure 7. Removing Top Plate and Weight 2100 AD DOCX Page 9 of 15

Note: Look for a blown out bearing seal in the grease at the top of the weight.

10 9.12 After the weight is resting on the cribbing, lift the top plate until the lead screw clears the weight. Note that the top plate / lead screw assembly is now top heavy; someone must hold the lead screw when it clears the weight because the lead screw will swing. Note: Look for a blown out bearing seal in the grease at the top of the weight. In 2015 we found three of the four to be blown out because when the bearing housings were greased, the pressure relief port was not opened Set the top plate / lead screw assembly down either on the ground (on a v block) or on a cart for easier access when disassembling the top plate (Figure 9). Figure 8. Weight Being Unscrewed from Lead Screw Figure 9. Top Plate Assy and Lead Screw 2100 AD DOCX Page 10 of 15

9.14 Choker sling the weight and rotate it to the horizontal position and lay it on v blocks on the ground. Orient it so both pieces of angle are about 90

Refer to drawing 2150 289 D020 DECLINATION AXIS COUNTERWEIGHT ASSEMBLY. Note that in 2015, new slides were installed and secured with brass pan head slotted screws.

11 9.14 Choker sling the weight and rotate it to the horizontal position and lay it on v blocks on the ground. Orient it so both pieces of angle are about 90 degrees from up or down (Figure 10) Clean the grease from the weight using degreaser Replace the B022 Nylon Slides and B023 Neoprene Slide Supports as required. Refer to drawing D020 DECLINATION AXIS COUNTERWEIGHT ASSEMBLY. Note that in 2015, new slides were installed and secured with brass pan head slotted screws. The neoprene spacers were not replaced as they were in perfect shape Using a hammer and a punch, punch out the taper pins that locate the gearbox mounting bracket on the top plate (Figure 11). Note that they must be punched from the bottom of the plate Remove the four bolts that secure the gearbox to the gearbox mounting bracket (Figure 12) 9.19 Remove the four bolts that secure the gearbox mounting bracket to the top plate (Figure 13) Figure 10. Weight Lying in V Blocks Figure 11. Taper Pins for Gearbox Mount Removal 9.20 Remove the drive coupling hub from the top of the lead screw (Figure 13) Remove the bearing housing from the top of the plate (not from the side with safetywired bolts. Don t take off the safety wire) (Figure 13) AD DOCX Page 11 of 15

23 Push the lead screw out of the bearing housing from the bottom of the plate. 9.

12 Figure 12. Gearbox Mounting Bracket 9.22 After the bearing housing is removed, remove the lock nut and lock washer (if the lock washer is still intact) from the lead screw Push the lead screw out of the bearing housing from the bottom of the plate Remove the bearings and spacer from the lead screw, clean, inspect, and replace if necessary In 2015, the original C010 nuts were removed from the weights and modified to accept new inserts. They exhibited about.015 to.020 inches of wear. The refurbished nut assemblies were installed onto D021 Figure 13. Bearing Housing 2100 AD DOCX Page 12 of 15

13 weights with four ⅜ 16 bolts. The bolts were tightened until light contact is made against the nut Reassemble counterweight assembly Wire the motors and run the weights up and down through their travel and check for problems. In 2015, Randy and Alfredo wired the motors in 480 three phase configuration (the motors are wired as 220 as installed). Power was taken from a breaker in the He compressor room at the south end of the console floor. The motor current was checked as the motors moved the weights. After this test, the counterweight assemblies are ready for reinstallation into the telescope AD DOCX Page 13 of 15

14 10. Declination Counterweight Installation Procedure Weight of Counterweight Assembly: 1700 lbf Weight of Counterweight including Nut: 1000 lbf (Both weighed during 2015 Summer Shutdown) 10.1 Ensure the telescope is in the Zenith position Ensure the Do Not Use placard is placed over control console, the telescope drives are locked out using the Lockout / Tagout procedure, and that the stay bars are installed Install one ½ lifting shackle in the each eyebolt Rig the system with the ends of two 4 foot lifting straps through each shackle and a ¾ shackle in the middle of one of the straps. Hook the ¾ shackle to the 5 ton crane hook Using the 5 ton crane, lift the counterweight assembly and move the 5 ton crane hook and counterweight assembly as close as possible to the chain hoist hook. Using a 12 foot strap wrapped around the bottom of the counterweight, pull the counterweight between the two corner Serrurier truss tubes Place the hook of the chain hoist on the loose 4 foot lifting strap that is not currently on the 5 ton crane hook. Center the hook on the strap as close as possible. Once the strap is secure, raise the hoist to transfer the weight of the counterweight assembly from the crane and onto the chain hoist Once the weight is taken by the chain hoist, remove the crane hook from the ¾ shackle Lower the counterweight into the counterweight mounting hole, taking care not to allow it to catch on anything as it descends Install ½ 13 Hex Head Bolts (3/4 Socket) from Counterweight Assembly flange Reinstall all wiring between telescope and Counterweight Assembly When all counterweights have been reinstalled, remove Dec and RA Staybars Unlock the telescope drives and remove the placard from the control console in the control room Balance telescope to prepare to rotate it. Rotate telescope down so the 12 foot straps and chain hoists can be removed from the top ring, or remove them using the personnel basket on the crane Rotate the telescope back up to vertical and test the counterweights by moving them through their full range of motion several times and listening for any unusual sounds and watching for binding or any other unexpected behavior Tighten the pusher bolts and their locknuts Synchronize the positions of all four counterweights AD DOCX Page 14 of 15

15 Procedure Review Once a year or as safety procedures or instrumentation mentioned changes Records 1. Record the dates and details of this maintenance in the 4m Log Book kept in the telescope control room. 2. Write a report, assign it a document number, and place it in the Engineering EPDM Vault 3. Write a note in Service to describing the dates of this maintenance including the document number of the report. 13. References KPNO Emergency Manual Job Hazard Analysis document 2100 AD JHA AD DOCX Page 15 of 15

Procedure for Disassembly and Removal of Top Portion of Central Baffle Stack from 4m Mayall Telescope

Doc #: 2100-AD-015-0061 Revision: - Procedure for Disassembly and Removal of Top Portion of Central Baffle Stack from 4m Mayall Author(s): Matthew Evatt Contents Revision History... 3 1.0 Purpose... 4