GE VERTICAL DRILLING MOTOR GE752 - Manual (Page 55)

Vertical Drilling Motor, Type GE752, GEK–91584D
55
Flood Dipping Coiled Frame
After field coils have been repaired or replaced and
electrical tests completed, insulate the coiled frame by
flood dipping in GE–8001 varnish. See Table 4, Page
55, for varnish viscosity limits.
Varnish may be thinned, as necessary, with Solves-
so* No. 100 thinner. Agitate varnish for 15 minutes be-
fore dipping frame.
1. Be sure all coil connections are made and insu-
lated, and all cables and ties for cables and con-
nection straps are in place. Tie cable ends above
the varnish level.
2. Coat all machine–fit surfaces with GE–271 black
varnish or stripping compound and plug bolt
holes with dummy bolts.
3. Heat the coiled frame to 40–80
_
C (104–176
_
F)
and dip the frame drive end down (with all coil
connections covered) for at least 15 seconds.
Drain and remove the frame from the varnish. Al-
low the frame to drain for at least 5 minutes in a
vertical position, drive end down.
4. Bake the frame in a pre–heated oven at 150
_
C
(302 _ F) for 30 minutes, minimum.
5. Clean the varnish from machined surfaces and
unplug the tapped holes.
TEST AFTER REPAIR
(Coiled Frame Without Armature)
1. Pass 24.0 amperes(60 Hz current) through the
exciting (series) field and read the voltage drop.
Minimum Volts 13.1 . . . . . . . . . . . . . . . . . . . . . .
Maximum Volts 15.6 . . . . . . . . . . . . . . . . . . . . . .
2. Pass 24.0 amperes (60 Hz current) through the
commutating (CP) field and read the voltage
drop.
For Non–Magnetic retainers:
*Standard Oil Co. of Pa.
0
10
20
30
40
50
60
70
0 10 20 30 40 50 60
TABLE 4
VARNISH VISCOSITY CHART FOR
DIPPING COILED FRAME
NOTE: When necessary, use Solvesso No. 100 to thin var-
nish.
GE NO. 8001 VARNISH
NO. 3 ZAHN CUP
TIME – SECONDS
TEMP. DEGREES C
FIG. 33. FIELD COIL POLARITY CHECK. E–888A.