GE GE752 manual Commutator Tightening, Procedure, Hydraulic Press Preferred Method

GEK±91584D, Vertical Drilling Motor, Type GE752

NOTE: Before rewinding the armature, first	2. Torque the commutator bolts by one of the fol-
check the shaft pinion and bearing fits to deter-		lowing methods.
mine whether or not shaft replacement is re-
quired. See Table 2 to determine the correct	Hydraulic Press (Preferred Method)
shaft drawings.	1.	Clean the front face of the cap and the segments,
The armature can be rewound using a GE Co. Sup-		Fig. 25. Remove ONE bolt at a time, and lubri-
		cate the bolt threads and under the bolt head.
ply Kit, Part 41D730545G8, and the information
		See Lubrication of Bolts section. Follow the se-
supplied in the kit.
		quence shown on Fig. 27 for bolt removal. Reas-
NOTE: After the armature is rewound, the arma-		semble bolt and tighten to the initial breakaway
ture coil leads must be TIG welded to the com-		torque value.
mutator risers, the armature must be Vacuum	2.	Using a depth micrometer, measure the distance
Pressure Impregnated, and the commutator
		(X in Fig. 25) between the face of the cap and the
must be cleaned and polished.
		segments at four points, 90 degrees apart. The
Commutator Tightening		face of the cap and the segments should be par-
		allel within 0.020 in. If necessary, tighten the ap-
If the commutator requires tightening, commutator		propriate cap bolts to obtain this parallel relation-
		ship between the face of cap and the segments.
assembly pressure can be restored at overhaul by per-
forming a commutator tightening procedure; however, it	3.	Place the armature in a vertical press. Position
is necessary that spin±seasoning and resurfacing oper-		ball and socket tool (Part 41C685080G1) and
ations be performed after the commutator is tightened.
		crow±foot pressing fixture (Part 41C685430G1)
Before proceeding to tighten a loose commutator, it		on the commutator, and apply 70 tons pressure
must first be determined whether or not the brush±sur-		at the diameter shown on Fig. 26.
face diameter of the commutator will be larger than the	4. Tighten the commutator bolts to 145 lb.±ft.
minimum permissible diameter after the commutator is
resurfaced.		torque in a crisscross sequence, Fig. 27. Tighten
If the brush±surface diameter is calculated to be		the bolts twice in this sequence, then tighten
		bolts once±around at 145 lb.±ft. torque.
smaller (after resurfacing) than the minimum
permissible diameter, listed in the DATA section, the	NOTE: The specified torque values have no sig-
commutator must be replaced.	nificance unless the bolts are lubricated.
After a long period of service, the mica insulation	5.	Check the dimension between cap face and seg-
		ments at four locations, 90 degrees apart, to as-
may relax, due to temperature cycling, and relieve com-
		sure surfaces are still parallel within 0.020 in.
mutator assembly pressure. This could result in a loose
commutator (with raised bars), or an out±of±round com-	Torque Wrench (Acceptable Method)
mutator.
	In the absence of a suitable press, bolts may be tight-
The assembly pressure can be restored by tighten-	ened with a torque wrench adjusted to apply the indi-
ing the commutator bolts. This must be done before un-	cated torque to each bolt.
dertaking any resurfacing operation on the commutator.	1.	Clean the front face of the cap and the segments.
Procedure		Using a depth micrometer, measure the distance
		(X in Fig. 25) between the face of the cap and the
		segments at four points, 90 degrees apart. The
1. Chip the weld from the commutator bolt heads to		face of the cap and the segments should be par-
free bolts from the cap.		allel within 0.020 in.

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