• SIGNA™ Hero 3.0T Service Methods
  • 5852800-8EN Revision 1.0
  • Object ID: 00000018WIA30AFC230GYZ
  • Topic ID: id_15667623 Version: 1.52
  • Date: Jan 26, 2022 3:32:57 PM

VRMw coil replacement

Prerequisites

Personnel requirements
Required personsPreliminary requirementsProcedureFinalization
3-3 days-
Tools and test equipment
ItemQuantityPart numberManufacturer
Nonmagnetic Hand Air Pump1--
Extension Cord1--
Vacuum Cleaner1--
Set: Nonabsorbent Protective Clothing (long sleeve shirt and pants)1 for each person--
Pair: Nonferrous Safety Shoes1 for each person--
Safety Glasses1 for each person--
Pair: Cut-Resistant Gloves1 for each person--
Gradient Coil Cart12134810-
Gradient Coil Insertion and Lift Kit12164744-8-
Universal Field Mapping Fixture Kit15266042-4-
Nonmagnetic Titanium Service Tool Kit, Large Set15112581-
Torque Wrench, 8-50 N m Adjustable, non-magnetic1

5534134 or 5534134-2

-
B0 Power Supply Kit12141701-
5 Gallon Pail12239133-
Dispenser of 100 #6005 Large N-DEX Nitrile Disposable Gloves Best #6005L146-194427P400-
Authorized Personnel Floor Sign (included with Safety Signage Kit 46-258770G4)12289812-
Magnet & Cryogen Manual - Passively Shimmed Magnets (Download from Online Document Library)1

5495018

-
Consumables
ItemQuantityPart numberManufacturer
Isopropyl Alcohol, 70%, USFS-2001--
Scour Pad (or equivalent)As Required-Scotch-Brite™
Cable Tie, 190 Wide X 14 large, nylon10046-252283P68-
Loctite #243 (check expiration date)15415261-3-
Loctite 271 (check expiration date)146-170684P2-
Never SeizeAs Required46294151P8-
Clean Lint-Free Towels (Kimwipes™)As Required--
Coolant (Note: Coolant will be reused. According to the remaining coolant in GCU, order it.)As Required5174313-4-
Required conditions

Order the non-magnetic torque wrench before starting this procedure.

If the magnet is ramped, remove all passive shim trays from the VRMw coil prior to the installation and store them in a safe place. See "Ref" column for applicable documentation containing procedures for removing the passive shim trays.

Procedure for replacing shim trays can be found in the Magnet and Cryogens Subsystem Manual. See Direction Number 5495018.

Table 1. Safety

About this task

Overview

This procedure describes the replacement of the VRMw gradient coil using Gradient Coil Insertion and Lift Kit 2164744-8.

Coolant will be reused after replacement. In case disposal of coolant is required, inform the customer that coolant disposal is needed and then follow the proper customer coolant disposal procedure.

Topic ID: id_SL15430853-1180648

Process flow of VRMw replacement

About this task

Table 2 covers all processes of VRMw Replacement with required person and estimated timings and it navigates to each procedure.
Table 2. Process flow of VRMw replacement
Process Hrs:Mins Required person Days
Power to ISC is turned off and LOTO procedures are implemented. See LOTO for ISC.0:1011st day

(12:30)

Undock the detachable patient table and move it outside the scan room.

:011
Remove the front endbell. See: Removing the front endbell:151
Remove the rear endbell. See: Removing the rear endbell0:151
For models with 1-piece bridge, remove the 1-piece bridge. Refer to Removing the 1-piece bridge:052

Remove the body coil.

See RF Body Coil Replacement (See step 5 to step 14 of “4 Procedure”.)

Note: Do not remove the front body coil mount since it is used when placing the body coil on the floor as illustration below.

1:303
STET Tool Setting

See Direction Number 5495018.

1:302
Remove all passive shim trays from the VRMw coil prior to the installation and store them in a safe place.

See Direction Number 5495018.

Passive shim trays are highly ferrous. Heed all warnings in Safety section above.

1:302
Remove STET

See Direction Number 5495018.

0:303
VRMw replacement (Remove)

From Coolant water removal to Moving VRMw with cart

3:303
VRMw replacement (Install)

From Preparation before installing VRMw to VRMw gradient coil installation.

2:303

  • Install the shim camera.

  • Install STET.

  • Restore the shim tray.

  • Connect B0 power supply to connection P304-1 on the magnet. Plug the B0 tester to AC power. Quench B0 coil in magnet by pressing and then holding the white button down for at least 1 minute.

  • Shim camera centering (If Axial 11 data remains. Otherwise, it should have be done before restoring the shim tray.)

  • Do Shimming.

See Direction Number 5495018.

WARNING: Passive shim trays are highly ferrous. Heed all warnings in Safety section above.

5:0022nd day

(11:00)

2:303

Add coolant to GCU.

0:301
:152
Return the patient table to the scan room and dock the patient table.

Remove LOTO at the ISC.

:051

Do Body Coil Tuning.

1:0013rd day

(14:20)

Do EPI White Pixel Test - Full Mode

0:301

Do a coherent noise test.

1:001

Do Auto DQA Cal. See DQA II Tool and Troubleshooting

0:301

Do DC Offset Adjustment

0:151

Do Grafidy 3 Eddy Current Calibration

1:001

Do Auto DQA cal (Final). See DQA II Tool and Troubleshooting

0:301

Do High Order Eddy Current (HOEC) Calibration

0:151

Do Dual drive quadrature tool

1:001
Do LV Shim (Grad Shim) 0:301
Wait for 2 hours Before starting B0 drift functional check.2:000

Do B0 Drift Functional Check

1:001

Do System Gain Calibration (Body).

0:301

Do the following tests.

1:301

Do MCQA for PA Coil Upper and MCQA for PA Coil Lower.

0:401
Do a SaveINFO to capture new calibration values.0:251
Topic ID: id_SL2998131-1180648

Coolant water removal

Procedure

  1. Make sure power to the ISC cabinet is turned off and LOTO procedures are implemented. LOTO for ISC
  2. Note: Wear nitrile gloves and safety glasses when removing coolant.
    Turn off the valve in coolant supply line at the service end of the magnet.
    Figure 1. Turn off the valve
  3. Place an empty five gallon bucket close to the service end to accept discharge coolant.
  4. Disconnect the supply and return hose for the gradient coil from the manifold valve assembly.
  5. Connect the pump air hose to the water return line on the VRMw coil using the hose barb provided with the gradient FRU kit.
  6. Drain fluid into Tank from return hose.
    Figure 2. Draining manifold coolant
  7. Pump the air pump and observe the coolant draining from the VRMw coil. Continue to drain coolant from the VRMw coil until no significant flow appears at the outlet draining into the container. This should take about five minutes.
    Note: Removed coolant can be returned to the GCU in the ICC later.
  8. Fold the supply and return manifold hose and use a cable tie to kink together, if necessary. (This is to form a closed loop of coolant line so water does not spill out during the VRMw coil removal.)
Topic ID: id_SL2914243-1180648

Cable removal and busbar disconnection

Procedure

  1. At the service end, remove the safety covers from the end of the Y and XZ busbar cable connections.
    Figure 3. Y and XZ busbar cables (service end)
  2. Note: DO NOT remove the clamps on the busbar leads.
    Figure 4. Clamp locations
    Remove the cable clamps.
    Figure 5. Cable clamps
  3. Remove six M10 nuts and Nord-Lock washers that are securing the busbar lugs to the coil. Slide the busbar terminal lugs off from the studs on the coil. Discard the Nord-Lock washers because they will not be reused.
    Note:

    Never use the nonmagnetic torque wrench to loosen connections, the torque wrench has a range of 10 - 50 N*m ( 8 – 35lbf*ft), removing Nord-Lock© or Spiralock© threads may exceed the limit of this wrench and destroy the ratchet components.

    Figure 6. Y and XZ busbar cable connections
  4. Unscrew the five screws with washers from the XZ busbar assembly.
    Note: This procedure is necessary when installing the tube support plate.
    Figure 7. XZ busbar assembly
  5. Remove the interface bracket from the gradient coil.
    Figure 8. Interface bracket
  6. Remove the four interface bracket studs for interface bracket from the gradient coil.
    Figure 9. Interface bracket studs
Topic ID: id_SL3115157-1180648

Cable removal

About this task

Remove the gradient coil ground cable.

Figure 10. Gradient coil ground cable
Topic ID: id_SL2914422-1180648

VRMw gradient coil removal

Procedure

  1. Attach three adapter plates (5338222) to the gradient coil patient end at 3, 9, and 12 o'clock positions with M10 x 20mm bolts. (See Figure 11 and Figure 13.) Attach one M10 nut to the bolts as shown in Figure 12.
    Figure 11. Adapter plate on gradient coil - patient end
    Figure 12. Bolt with nut installed
  2. Attach two adapter plates (5338223) to the gradient coil service end at the 3 and 9 o'clock positions with M10 x 20mm bolts as shown in Figure 13. Attach one M10 nut to the bolts as shown in Figure 12.
    Figure 13. Adapter plates on gradient coil - service end
  3. Obtain the two tube guide roller assemblies (5308402) and mounting plates (5161983, 5161985) from the gradient coil insertion and lift kit shipping crate. Make sure the tube guide roller assemblies are tightly attached to the VRMw mounting plates.
    Figure 14. Roller assembly and mounting plates
    Item Description
    1Mounting Plate, Patient End
    2Mounting Plate, Service End
    3Roller Assemblies
  4. Attach adapter plate (5338224) to the gradient coil service end at the 12 o'clock position with M10 x 20mm bolts. (See Figure 11.) Attach one M10 nut to the bolts as shown in Figure 12. Different adapter plates are used for the front and rear of the gradient coil.
  5. Align the mounting holes of the patient end mounting plate (5161985), including guide roller assembly, with adapter plates (5338222), which are already attached to the gradient coil. Secure installation plate to the adapter plates using M10 x 20mm bolts and M10 nuts.
    Figure 15. Mounting plate with roller assemblies - patient end
  6. Align the mounting holes of the service end mounting plate (5161983), including guide roller assembly, with adapter plates (5338223 and 5338224), which are already attached to the gradient coil. Secure installation plate to the adapter plates using M10 x 20mm bolts and M10 nuts.
    Figure 16. Mounting plate with roller assemblies - service end
  7. Remove two axial stops from rear end.
    Figure 17. Removing the rear axial stop
    1M10 x 30 mm Bolt, Brass
    2M10 Nut, Brass
    3Rear Axial Stop
    4Stud on Axial Stop
  8. Retrieve the Tube Support Plate Assembly (2284928-2) from the Gradient Coil Insertion and Lift Kit shipping crate
  9. Remove the two lower standoffs from the tube support plate.
    Figure 18. Lower standoffs of tube support plate
  10. Attach the Wing Adapters (5339882, Item 2) to the tube support plate with stainless steel 0.75 in. 16 x 1.25 in. long bolts.
    Figure 19. Support plate with wing adapters
  11. Before installing the tube support plate, remove the rear service end wedges at the 1 and 2 locations.
    Figure 20. Systems with 10 wedges: Axial stops and wedges
  12. Attach the tube support plate to the magnet service end by inserting the 100 mm M10 x 25 stainless steel studs (5303994) 3/8 in. (13 mm) into the magnet, and secure them with the stainless steel washers and M10 nuts from the Gradient Coil Insertion and Lift Kit.
    Figure 21. Support plate attached on the interface ring
  13. Remove axial stops from patient end of the magnet.
  14. Remove wedges at locations 3 through 6 (in that order) from the patient end of the magnet.(See Figure 20.) Do not remove wedges from locations 7 and 8 at this time.
Topic ID: id_SL4806936-1180648

Moving VRMw with cart

Procedure

  1. Place tube jack assembly (5191132) in the cart. Make sure the back of the jack assembly fits properly into the cart.
    Figure 22. Jack assembly placement
  2. Maneuver the cart to the patient end of the magnet, and position it in front of the magnet with at least a 2 in. (50.8 mm) gap between the cart and the magnet interface ring (required for lower wedge removal.)
    Figure 23. 2-inch gap between the magnet and cart
  3. Center the cart left-to-right with respect to the magnet bore, and adjust the height of the cart to match the magnet opening.
  4. Release the hand lever on the cart handle to set the brakes. This will keep the cart from moving after the cart is aligned with the bore.
  5. Retrieve the male Insertion Tube (2284929) and Tube Standoff (5191626).
    1. Attach the tube standoff to the male insertion tube using the 4 inch, 0.375-16 UNC hex socket screw (5303993) included in the gradient coil insertion and lift kit.
    2. After the standoff is secured to the tube, attach the tube pilot shaft to the standoff.
    Figure 24. Attaching the standoff to the insertion tube
  6. Remove the PVC shield from the brass thread of the male insertion tube.
    Figure 25. PVC shield for brass thread
  7. Slide the male insertion tube through the tube guide roller assemblies at both sides of the Gradient Coil, push the pilot shaft through the support plate mounting bearing, and insert a nonmagnetic safety pin through the hole in the pilot shaft.
    Figure 26. Tube pilot shaft and support plate
  8. With one person holding the male insertion tube to keep it from rolling, two people should obtain the female insertion tube from the shipping crate and thread the two tubes together.
    Note: Each of the two pieces of the gradient insertion tool weighs less than 35lb (15.9kg).
    Figure 27. Setting up insertion tube assembly
  9. Recheck the centering of the cart left-to-right with respect to the magnet bore, and adjust the longitudinal alignment of the cart if required.
  10. Remove the remaining wedges (3~8 from Service End, 1-2, 7-8 from Patient End).
  11. Simultaneously raise the tube jack and the support plate mounting bearing to lift the Gradient Coil.
    Figure 28. Raising VRMw gradient coil
  12. While keeping the coil as close to level with the magnet bore, lift the coil high enough to remove the gradient mounting pad, and remove it from the rear end of the magnet.
  13. Lower the gradient coil and adjust it left-to-right to keep the coil centered in the magnet bore. Adjust as necessary.
  14. Slowly push the gradient coil out of the magnet bore while watching the clearances to the left, right, top, and bottom; adjust the tube jack and support plate mounting bearing as required to keep the coil from touching the magnet bore surface.
  15. Rotate the gradient coil until the return coolant line at service end is oriented downwards.
  16. Gradually lower the tube jack and the support plate mounting bearing until the weight of the gradient coil settles on the cart.
  17. Properly secure gradient coil to coil cart with Shipping Brackets (5357473).
    Figure 29. Shipping brackets (example at one location)
  18. Remove the insertion tool from the Gradient Coil per following steps.
    1. Remove safety pin from the support plate.
      Figure 30.
    2. Slide out the insertion tool until the joint can be seen.
    3. With one person holding the male insertion tube to keep it from rolling, two people remove the female tube from the male tube.
    4. Remove the male insertion tube with two people.
    Note: Each of the two pieces of the gradient insertion tool weighs less than 35lb (15.9kg).
    Figure 31. Removal of tool
  19. Using 3 persons, move Gradient Coil and cart out of magnet room.
  20. Remove the mounting plates from the Gradient Coil.
    Figure 32. Mounting plates removal
Topic ID: id_SL2915557-1180648

Preparation before installing VRMw

Procedure

  1. While wearing nitrile gloves, wipe the magnet bore using a clean towel and isopropyl alcohol.
  2. Examine the electrical connection terminals at the Gradient Coil service end.
    1. Inspect the copper terminal surface and the stud thread of the gradient terminals for gauges, surface damage, and any epoxy or threadlocker contamination.
    2. If necessary, clean with an abrasive pad and wipe with alcohol wipes.
  3. Attach three adapter plates (5338222) to the Gradient Coil patient end at 3, 9, and 12 o'clock positions with M10 x 20mm bolts. (See Figure 33 and Figure 35.) Attach one M10 nut to the bolts as shown in Figure 34.
    Figure 33. Adapter plate on the gradient coil - patient end
    Figure 34. Bolt with the nut installed
  4. Attach two adapter plates (5338223) to the Gradient Coil service end at the 3 and 9 o'clock positions with M10 x 20mm bolts. (See Figure 35.) Attach one M10 nut to the bolts as shown in Figure 34.
    Figure 35. Adapter plates on the gradient coil - service end
  5. Attach adapter plate (5338224) to the Gradient Coil service end at the 12 o'clock position with M10 x 20mm bolts. Attach one M10 nut to the bolts as shown in Figure 34.
  6. Remove the shipping brackets that are securing the Gradient Coil to the cart.
    Figure 36. VRMw shipping bracket
  7. Remove the Gradient Coil cradle fasteners, two per side, from the cradle.
    Figure 37. Removing cradle fasteners
  8. Use a vacuum cleaner to clean up the Gradient Coil inside and out. Remove any possible metal dust/shavings off the coil.
  9. Obtain the two tube guide roller assemblies (5308402) and mounting plates (5161983, 5161985) from the Gradient Coil insertion and lift kit shipping crate. Make sure the tube guide roller assemblies are attached to the mounting plates.
    Figure 38. Roller assembly and mounting plates
    Item Description
    1Mounting Plate, Patient End
    2Mounting Plate, Service End
    3Roller Assemblies
  10. Align the mounting holes of the patient end mounting plate (5161985), including guide roller assembly, with adapter plates (5338222), which are already attached to the gradient coil. Secure installation plate to the adapter plates using M10 x 20mm bolts and M10 nuts.
    Figure 39. Mounting plate with roller assemblies - patient end
  11. Align the mounting holes of the service end mounting plate (5161983), including guide roller assembly, with adapter plates (5338223 and 5338224), which are already attached to the Gradient Coil. Secure installation plate to the adapter plates using M10 x 20mm bolts and M10 nuts.
    Figure 40. Mounting plate with roller assemblies - service end
  12. Obtain the male insertion tube (2284929) and tube standoff (5191626).
    1. Attach the tube standoff to the male insertion tube using the four-inch, 0.375-16UNC hex socket screw (5303993) included in the Gradient Coil insertion and lift kit.
    2. After the standoff is secured to the tube, attach the tube pilot shaft to the standoff.
    Figure 41. Attaching the standoff to the insertion tube
  13. Remove the PVC shield from the brass thread of the male insertion tube.
    Figure 42. PVC shield for brass thread
Topic ID: id_SL2916576-1180648

VRMw gradient coil installation

Procedure

  1. Obtain tube support plate assembly 2284928-2 from the Gradient Coil insertion and lift kit shipping crate.
    1. Make sure the two Wing Adapters (5339882) are attached with 0.75 inch, 16 x 1.25 in. long stainless steel bolts (1).
    2. Secure the tube support plate assembly and wing adapters to the magnet flange at the service end with M10 studs, spacers, and M10 nuts (2).
    Figure 43. Attaching the tube support plate
  2. Adjust the tube support plate assembly's horizontal adjustment screws until the tube support bearing is centered left-to-right.
    Figure 44. Adjusting the support plate
    1Spacer
    2Vertical Adjustment Lever
    3Horizontal Adjustment Screw
    4Support Bearing
  3. Place the tube jack assembly (5191132) in the cart. Make sure the back of the jack assembly fits properly into the cart.
    Figure 45. Jack assembly placement
  4. Maneuver the cart and gradient coil to the patient end of the magnet, and position it in front of the magnet with at least a 2 in. (50.8 mm) gap between the cart and the magnet interface ring (required for lower wedge removal)
    Figure 46. 2-inch gap between the cart and magnet
  5. Center the cart left-to-right with respect to the magnet bore.
  6. Release the hand lever on the cart handle to set the brakes. This will keep the cart from moving after the cart is aligned with the bore.
  7. Raise or lower the cradle of the cart as required to vertically align the tube support plate at the magnet and the gradient mounting plates at the Gradient Coil.
    Figure 47. Adjusting the height of the cart
  8. Slide the male insertion tube through the tube guide roller assemblies at both sides of the Gradient Coil. Make sure the end with the standoff and pilot shaft faces towards the magnet.
  9. With one person holding the male insertion tube to keep it from rolling, two people should obtain the female insertion tube from the shipping crate and thread the two tubes together.
    Figure 48. Setting up the insertion tube assembly
  10. Push the complete insertion tube assembly into the magnet bore. Get the tube pilot shaft as close to (but not touching) the tube support plate as possible.
    Figure 49. Complete the insertion tube assembly
  11. Align the support plate mounting bearing with the tube pilot shaft by adjusting the vertical height of the support plate bearing using the stainless steel lever, and/or raising or lowering the cart.
  12. Meanwhile recheck the centering of the cart left-to-right with respect to the magnet bore. Adjust cart longitudinal alignment if required.
  13. Push the pilot shaft through the support plate mounting bearing. Insert a nonmagnetic safety pin through the hole in the pilot shaft.
    Figure 50. Tube pilot shaft and support plate
  14. Raise the tube jack and support plate mounting bearing to lift the gradient coil up. Keep the coil approximately level with the magnet bore during the lifting. The coil should be able to rotate freely when completely lifted off the cart.
    Figure 51. Raising the gradient coil
  15. Rotate the gradient coil, if necessary, until the electrical connection terminals at the gradient coil's service end is oriented upwards.
  16. Slowly push the gradient coil into the magnet bore while watching the clearances to the left, right, top and bottom. Adjust the tube jack and support plate mounting bearing as required to keep the gradient coil from touching the magnet bore surface.
  17. Note: Be sure to keep hands and loose clothing away from bore as coil is being moved into the magnet bore.
    Slowly push the gradient coil until it is close to the tube support plate at magnet service end. Raise the support plate bearing to gain more clearance between the coil and the lower base plates if necessary.
  18. At the magnet patient end, attach the gradient alignment T-block and the gradient coil radial alignment tool as follows.
    1. Mount the gradient alignment T-block (5389303) to the gradient coil patient end, using two M10x25 SS FHSCS (5389090-3) at –15deg and +15deg hole in the coil’s flange.
    2. Mount the gradient alignment tool (5266402) to the magnet patient end, using 2 M10x25 SS bolts (46-318508P20) at –15deg and +15deg hole in the magnet interface ring.
    Figure 52. Gradient alignment tools
  19. Carefully roll the gradient coil and stop the coil when the T-block (5389303) starts to make contact with the alignment tool (5266408).
    Figure 53. Aligning gradient coil (front-to-back)
  20. Align the coil clocking direction as follows.
    1. Roll the gradient into position until the center hole of the alignment T-block (5389303) aligns with the slot of the alignment tool (5266408) on the magnet.
    2. Place the thumbscrew (part of the gradient alignment tool) though the slot and thread it into the alignment T-block on the coil. Engage the rotational locks on the carriage assembly to hold the position.
    Figure 54. Aligning the gradient coil (clocking)
  21. Make sure the gradient axial and radial alignment has not changed. Install the pad under the coil as following step.
    1. Before lowering the gradient into place, install the gradient isolation blanket (5473683).
    2. Insert the RF shield retainer (2104944-7) between the gradient and warm bore all the way through.
    3. Using Gorilla tape (46-252065P151), tape the ends of two RF shield retainers (large G10 shims) to the end of the isolation blanket.
    4. Carefully position the end of the blanket that is taped under the rear end of the gradient ensuring that the blanket is flat on the inside surface of the bore.
      Figure 55. Position the blanket
    5. Once the blanket is flat in the bore, partially under the gradient, on the rear end of the magnet, use the RF shield retainer (large G10 shims) to pull the blanket through smoothly, being careful not to damage the blanket. The process may require alternating the pull between shims to inch the blanket through the bore.
      Note: Remove the RF shield retainer after the RF isolation blanket is installed.
    6. The blanket should be even with the gradient, approximately 110 +/- 10 mm from each end of the bore.
      Figure 56. Pull the blanket
  22. Slowly lower support plate bearing and tube jack.
  23. Make sure the gradient axial and radial alignment has not changed.
  24. Re-install the Axial Stop Assembly for patient at the patient end of the magnet. Make sure that the Gradient Coil is making contact with the patient end axial stops. Slowly lower the Gradient Coil onto the pads. Release pressure on the beam, so that the coil is supported by the mounting pads.
    Figure 57. Lowering the gradient coil with the radial alignment tool
  25. Remove the radial alignment tool and T-block. Return them to the gradient insertion kit shipping crate.
  26. Tighten the axial stop stud towards the Gradient Coil to a torque of 10~12 ft-lbs. In presence of magnetic field, use hand-tight (until resistance felt) plus 1 full turn with a non-ferrous screwdriver. Tighten the M10 brass nut on the coil side of the axial stop bracket to 10~12 ft-lbs. In presence of magnetic field, use hand-tight (until resistance felt) plus 1/2-turn.
    Figure 58. Axial stop
    Item Description
    1M10 x 30 mm Bolt, Brass
    2M10 Nut, Brass
    3Rear Axial Stop
    4Stud on Axial Stop
  27. At service end, remove the Wing Adapters (5339882) from the tube support plate to proceed the next step.
  28. Do Step 26 for service end of the magnet to secure the stop.
  29. Install the four top wedges (5566938) (with one M10 x 24 mm washer and one brass M10 x 35 mm hex head bolt per wedge) on the patient end of the magnet flange in the order shown Figure 59 from 1 to 4
  30. Install the four bottom wedges (5566941) (with one M10 x 24 mm washer and one brass M10 x 35 mm hex head bolt per wedge) on the patient end of the magnet flange in the order shown in Figure 59 from 5 to 8.
    Figure 59. Installation sequence of stops and wedges

    After the wedge is fitted firmly into the slot, secure it to the gradient coil flange using one G10 washer (5146169) and one brass hex head M10 x 35 screw (5110638-65) with Loctite 263 or 271.

    • Loctite 263 or 271 should be applied to the engagement portion of the brass bolt.

    • Do not drive the wedge to contact the gradient coil structure.

    • There should be a gap between the wedges and the gradient coil flange after tightening all the bolts.

    • If a bolt appears to be bottomed out earlier, use a second G10 washer (5146169).

    • Do not use more than two (2) washers on any one location.

    Tighten the brass bolts (in the same order, pair-by-pair, as the wedges were installed) securely to the stops and wedges.

  31. Repeat Step 29 and Step 30 at the service end of the magnet to secure the wedges.
  32. Remove the gradient coil insertion and lift kit from VRMw and magnet.
  33. Note: Observe the following:

    • Always use the new Nord-Lock washers that come with the FRU package. DO NOT reuse the old Nord-Lock washers.

    • Nord-Lock washers consist of two pieces, which are generally glued together. Always use a complete set with two pieces joined together in correct orientation. DO NOT use a separated single piece.

    Figure 60. Nord-Lock washers
    Re-install busbar cables to new gradient coil. Place a new Nord-Lock washer over each stud.

    After putting the cable connection on the stud, place a new Nord-Lock washer over each stud.

    Put two drops of Loctite 243 on the exposed thread. (Shake the bottle first.)

    Do not get Loctite on the Nord-Lock washer.

    Hand-tighten the nut.

    Discard the old washers.

    Installation Sequence:

    1. Power cable lug

    2. Nord-Lock washer

    3. Brass nut

    Figure 61. Loctite on the stud
    Figure 62. Installation of the busbar cables to the new gradient coil
  34. Set the torque wrench to 25 ft-lbs or 33.9 Nm. Install 15 mm socket on the extension.
    Note: Make sure that the arrow on the torque wrench is visible. If the arrow is not visible, the torque wrench will not “click” when the proper torque is reached.
    Figure 63. Arrow on Non-magnetic torque wrench
  35. Torque the nut in the direction of the arrow until the torque wrench reaches the break point.
  36. Using a Sharpie pen, place a line from the base of the stud to the nut.
    Figure 64. Stud and the nut marked to show torque position
    Item Description
    1Black line on the nut and stud to show torque position.
  37. Do a second torque operation at each nut to confirm the proper torque of the nut.

    If the nut moved more than one flat from the original position, you must re-torque the nut a third time.

    If re-torquing was required, re-mark the line on the nut and stud.

  38. Reinstall cable clamps.
  39. Restore the XZ busbar assembly with 5 screws and washers.
  40. Reinstall the safety covers over the cable.
    Figure 65. Y and XZ busbar cables (service end)
  41. Connect the VRMw supply and return hoses to the copper block and secure the connection with stainless steel hose clamps.
  42. Open the coolant valve at the rear of the magnet.
    Figure 66. Hose connections for gradient return and supply
  43. Remove all parts of the gradient insertion tool from the VRMw gradient coil and return to the crate. Properly store all components.
Topic ID: id_15838475

Finalization

Procedure

  1. Return the VRMw with the cart (originally stored in local stock) as it was shipped and restore the cart (originally shipped with FRU) to the local stock.
    Figure 67. VRMw cart operation
  2. Make sure all the items in Table 2 were completed.