(2) Oil lubricated motors are shipped without oil. When storage time exceeds one (1)
month, the oil sumps must be filled to the maximum capacity as indicated on the oil
chamber sight gauge window. Refer to motor lubrication nameplate or Table 5 for
proper oil.
NOTE: Motor must not be moved with oil in reservoir. Drain oil before moving to prevent sloshing and
possible damage. With a clean cloth, wipe any excess oil from the threads of the drain plug
and the inside of the drain hole. Apply GASOILA®† or equivalent thread sealant to the threads
of the drain plug and replace the plug in the oil drain hole. Refill oil when motor has been
moved to the new location.
G. To prevent moisture accumulation, some form of heating must be utilized. This heating should
maintain the winding temperature at approximately 5'C above ambient. If space heaters are
supplied, they should be energized. If none are available, single phase or 'trickle' heating may
be utilized by energizing one phase of the motor's winding with a low voltage. Request the
required voltage and transformer capacity from Nidec Motor Corporation. A third option is to
use an auxiliary heat source and keep the winding warm by either convection or blowing
filtered warm air into the motor.
3.3 Periodic Maintenance
A. Oil should be inspected monthly for evidence of moisture or oxidation. The oil must be replaced
whenever contamination is noted or every twelve months; whichever occurs first. It is important
to wipe excess oil from the threads of the drain plug and the drain hole and to coat the threads
with GAS0ILA"1 or equivalent thread sealant before replacing the drain plug.
B. Grease lubricated bearings must be inspected once a month for moisture and oxidation by
purging a small quantity of grease through the drain. If any contamination is present, the
grease must be completely removed and replaced.
C. All motors must have the shaft rotated once a month to maintain a lubricant film on the
bearing races and journals.
D. Insulation Testing:
Two tests are used to evaluate the condition of the winding insulation. The first of these is the
one minute insulation resistance test (IR1) and the second is the polarization index test (Pl),
which can also be referred to as a dielectric absorption test. The results of either of these
tests can be skewed by factors such as the winding temperature and its relation to the dew
point temperature at the time the test was conducted. The Pl test is less sensitive to these
factors than the IR, test, but its results can still be affected significantly. Due to these factors,
the most reliable method for evaluating the condition of the winding insulation is to maintain
a record of periodic measurements, accumulated over months or years of service, for one or
both of these tests. It is important that these tests be conducted under similar conditions of
winding temperature, dew point temperature, voltage magnitude and duration, and relative
humidity. If a downward trend develops in the historical data for either test, or if the readings
from both tests drop below a minimum acceptable value, have an authorized electrical
apparatus service shop thoroughly clean and dry the winding, and retreat, if necessary.
