GE GE752 manual GROUNDING PROCEDURES Fig, Overhaul, Lubrication, Grease Tubes And Pipe Plugs

Vertical Drilling Motor, Type GE752, GEK±91584D

decks by bolting or welding should not require additional grounding. (References: ABS Rules for Building and Classing Steel Vessels, Section 35.9.6, and IEEE Stan- dard 45±1977, Recommended Practice for Electrical In- stallations on Shipboard, Section 21.4.)

GROUNDING PROCEDURES (Fig. 2)

Most GE drilling machines have extra tap blocks on the frame for mounting of the connection boxes. One of these may be used for attaching the grounding cable. If one is not available, use the lower chain case mounting boss on the end opposite the drive end in accordance with Step 2.

1.To attach the ground cable to a tap block, obtain a 0.75±10 bolt with length of 1.0 to 1.5 in. and a lockwasher. Also obtain a cable lug to fit the ground cable and large enough for the 0.75 di- ameter bolt.

2.To attach the cable to the chain case boss, obtain a 1.25±7 bolt with length of 1.0 to 1.75 in. and a lockwasher. Prepare a copper plate at least 1/8 in. thick with a 1.25 in. diameter hole for bolting to the chain case boss, and with enough extra area for holes to attach a cable lug. Drill hole(s) in plate for cable lug. Clean all paint, rust and oil from the chain case boss and bolt the copper plate to the chain case boss.

3.Prepare a ground conductor* long enough to run from the motor frame to an existing ground con- ductor system or to a suitable equipment ground point as defined by the National Electrical Code Article 250 or other applicable regulation. Check that the system ground detector is also con- nected to the Common ground point for the rig and make connection if necessary.

4.Install terminal lugs on cable. Remove paint, rust and oil from the surfaces to which the cables are to be attached and bolt the lugs securely to these surfaces.

*Use 4/0 size or larger copper cable for GE752 ma- chines. (Reference: National Electrical Code, 1978 Edition, Table 250±95.)

5.Use a digital ohmmeter to check that the bolted connections are solid, low resistance connec- tions from the cable conductor to the ground point and to the motor frame. The meter reading should be 0.2 ohms or less.

OVERHAUL

Overhaul intervals will depend on the severity of ser￿ vice seen by the machine. However, General Electric Co. recommends that an overhaul be performed every 18,000 hours (approximately every two years) on all machines subjected to normal operation.

The motor should be removed, disassembled, cleaned, inspected and reconditioned as necessary (in- cluding varnish treatment of armature and fields). Motor bearings should be repacked with grease. See the DATA section for grease type and quantity.

LUBRICATION

Periodic lubrication is required on all GE752 drilling machines designed for vertical operation between scheduled overhaul periods. Every six months or 2500 hours, whichever comes first, apply approximately 2 oz. of grease at each end.

GREASE TUBES AND PIPE PLUGS

The following lists grease tube and pipe plug configu- rations for all models covered in this publication:

1.UP1 and AUP1 Ð Four grease tubes with pipe plugs, two at each end.

2.UP2 and AUP2 Ð Two grease tubes with pipe plugs, one at each end.

3.UP3, UP3A, UP4, UP5, UP6, AUP3, AUP4, AUP5 ± One grease tube with a pipe plug at the drive end, one pipe plug only at the commutator end.

4.US1, US2, AUT1, AUT2 ± One pipe plug only at each end.

Pipe plugs are provided on bearing caps and on the ends of all grease tubes to prevent the ingress of dirt or other contamination.

Remove the pipe plugs and install grease fittings to facilitate lubrication. Replace the pipe plugs after adding lubricant. See the DATA section for recommended grease type.

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