Manual for Induction Motors and Generators
Trouble Shooting -
101
3BFP 000 050 R0101 REV E
***Following chapter for bearing type: Sleeve bearing with flood lubrication
8.2.4 Oil container and piping
A separate oil container and piping is used only for flood-lubricated bearings.
Oil container
The oil container can be either a separate container, or in some cases, the crankcase of a diesel
engine. In both cases, the container has to be well below the bearings, in order for the oil to flow
to the container from the bearing.
The oil container should be constructed in such a way that no pressure can enter the oil return
piping from the container towards the bearing.
Oil piping
The function of the oil return piping is to allow the oil to return to the oil tank with as little of
friction as possible. This is normally obtained by choosing a piping diameter of a large enough
diameter, so that the flow of the oil in the return line does not exceed 0.15 m/s (6 inch/s) based
on the pipe cross section.
Install the oil outlet pipes downwards from the bearings at a minimum angle of 15° which
corresponds to a slope of 250 - 300 mm/m (3 – 3½ inch/ft).
The assembling of the piping must be performed in such-a-way that above mentioned slope is
present at all points of the piping.
***Following chapter for bearing type: Sleeve bearing with flood lubrication
8.2.5 Oil container and piping verification
In case the oil leakage is suspected to originate from the construction of the oil container or the
oil piping, the following steps can be taken:
Pressure in oil container
The atmospheric pressure inside the oil container must be verified. The pressure may not be
larger than the pressure outside the bearing. If this is the case, a breather must be installed to the
oil container.
Oil piping
It should be verified that the piping has a sufficient diameter, is not clogged, and that the slope is
downward and sufficient throughout the oil return piping.
