HWMA2 USER INSTRUCTIONS ENGLISH - 06/16
Page 18 of 39
5.2.4 Oil quality
Oil used for lubrication should only be of high quality.
The viscosity of the oil at working temperature must
be at least 10 cSt. The pouring point of the oil must
be in accordance with the lowest expected
temperature of the bearing housing during a stop of
the pump. For recommended lubricating oils refer to
the lubrication table.
Having selected the corresponding oil quality the
actual oil temperature at the bearing housing must be
checked after two service hours of the pump.
Considering this measured oil temperature the actual
viscosity must be determined by using the data sheet
of the oil, to verify the minimum required viscosity of
10 cSt. Do not forget, the oil temperature in the
bearing itself is about 10 °C (Δ 18 °F) higher than the
oil
temperature at the bearing housing. On the
following
table the oil viscosity is given at 40 °C (104
°F). Determining the correct lubricating oil one must
take into consideration that all bearings will have
higher temperatures during the first 20 service hours.
In constant operation the bearing temperature will
decrease about 10 °C (50 °F). The oil temperature
shall be lower than 85 °C (185 °F) after this running-
in time. The bearing outer race temperature should
not exceed 95°C (203°F). If the temperature is higher,
the reason may be a wrong oil quality, wrong oil level
or overload of the pump because of excessive wear.
If the humidity at the site is high, the roller bearings
become easily rusty during stand still periods. To
avoid that, we recommend to mix the lubricating oil
with a corrosion inhibitor contact your lubrication oil
supplier for proper additives inhibitors.
