ORNL-1771 - Oak Ridge National Laboratory

MOTOR
SlATOR TAPE GLASS
BRUSH HOLDER PLATE MICA
PERIOD ENDING SEPTEMBER IO, 7954
UNCLASSIFIED
ORNL-1.R-DWG 20814
'HFARING, FAFNIR DVJ-6 \THERMOCOUPLE RPM COIL 'NSTRUMFNT LEADS '
DELCO,AC-DC, '115 hp, SFRVICE NO 5047431
RPM COIL NO 36 A W G CCROC, 200-5500 TURNS
BFARING GREASE RRG-2 (NL.GI GRADE 2)
test a brush holder plate of mica backed with a
stainless steel plate was used, In the second test
fired Lavite asbestos covered wire was used from
the brush holder to the field coil. Glass tape was
used around the field coils.
The rest of the construction features were un-
altered; that is, fish-paper-coil supports, plastic
(paper-backed Bake1 ite) commutator segment
spacers, and cardboard armature shaft spacers
were used.
The upper bearing (New Departure 77R6) and
lower bearing (Fafnir DW-6) were packed with
California Research Corporation grease, identified
as RRG-2 [NLGl Grade 21.
The RPM meter consists of a magnet fastened to
the shaft which will rotate inside the gas-tight
motor shell. A coil wound around a C-shaped iron
core is mounted outside the shell. As the shaft
rotates, pulses aregenerated in the coil and counted
remotely by a frequency meter calibrated in rprn.
The coil was wound with 36-9 Ceroc 200 magnet
wire covered with glass tape impregnated with
Glyptol. Summary data on the test conditions are
given in Table 9.1.
The motors were examined, after irradiation, in
the* hot cell. Assistance was given in hot cell
examination by J. Noaks and J. Crudele, Pratt &
Whitney Aircraft Division. A withdrawal cask and
its facilities were loaned by L. E.Stanford, General
Electric Company.
Fig. 9.3. Motor and RPM Meter Test Assembly.
TABLE 9.1. CONDITIONS OF TEST MOTOR AND
RPM METER ASSEMBLY
Motor load
Test No. 1 Test No. 2
d-c voltage 60 33
Current, amp 0.45 0.20
Shaft speed, rprn 4500 4500
Fufnir bearing
temperature, 'C
45 45
Motor field plate
temperature, OC
65 40
Time of operation
At 4500 rprn, hr 100 648
In flux,* hr 84 613
*Thermal flux, 5 x 10" neu+rons/cm2-sec; ratio of fast
to thermal neutrons, 1; gumma field, 4.4 r/hr.
In the first test, motor load was abnormally great
from the beginning and the field plate temperature
was high. When the motor failed after 100 hr,
the stator temperature rose to 182OC while the
power was kept on. The suspicion that there was
a cocked upper bearing plate was confirmed upon
postirradiation examination (Fig. 9.4). The sensing
coil for the RPM meter functioned well; there was
no resistance change or visual deterioration.
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