11239449 Installation, operation and maintenance manual – Squirrel cage motor – W Line - Horizontal and vertical l 39
7.10
BEARING MAINTENANCE
7.10.1
Grease-lubricated rolling bearings
7.10.1.1
Instructions for lubrication
The lubrication system was designed in such a way that
during the lubrication of the rolling bearings, all the old
grease is removed from the rolling bearing races and
expelled through a drain which enables the exit of the
grease, but prevents the ingress of dust or other harmful
contaminants.
This drain also prevents damage to the rolling bearings by
the known problem of excessive lubrication.
It is recommended to make the lubrication with the motor
in operation in order to ensure the renewal of the grease in
the rolling bearing housing.
If that is not possible due to the presence of rotating parts
near the grease nipple (pulleys, etc.) which may put the
operator at risk, follow the procedures below:
With the motor stopped, inject approximately half of the
total intended amount of grease and operate the motor
for approximately one minute at full speed;
Stop the motor and inject the rest of the grease.
ATTENTION
The injection of all the grease with the
motor stopped may lead to the penetration
of part of the lubricant into the motor
through the internal seal of the rolling
bearing cap;
It is important to clean the grease nipples
prior to lubrication in order to prevent
foreign materials from being dragged into
the rolling bearing. For lubrication, use only
manual grease gun.
NOTE
The rolling bearing data, amount and type
of grease, and lubrication intervals are
informed on a bearing nameplate affixed to
the motor.
Check this information before performing
the lubrication.
The lubrication intervals informed on the nameplate
consider a 70 °C working temperature of the rolling
bearing;
Based on the operating temperature ranges listed in
Table 7.1, apply the following correction factors for the
rolling bearing lubrication intervals:
Table 7.1: Reduction factor for lubrication intervals
Bearing operating temperature
Reduction factor
Below 60 ºC
1.59
Between 70 and 80 ºC
0.63
Between 80 and 90 ºC
0.40
Between 90 and 100 ºC
0.25
Between 100 and 110 ºC
0.16
7.10.1.2
Procedures for rolling bearing
relubrication
1.
Remove the drain plug;
2.
Clean with a cotton cloth around the hole of the
grease nipple;
3.
With the rotor operating, inject the grease with a
manual grease gun until grease starts coming out from
the drain or until the proper amount of grease,
informed in Table 7.3, has been injected.
4.
keep the motor running long enough so that the
grease excess passes through the drain;
5.
Inspect the bearing temperature to make sure there
was no significant change;
6.
Put the drain plug back in place.
7.10.1.3
Rolling bearing relubrication with drawer
device for grease removal
In order to relubricate the bearings, the old grease is
removed by means of the device with a drawer installed
on each bearing.
Lubrication procedure:
1.
Before starting the lubrication of the bearing, clean the
grease nipple with a cotton cloth;
2.
Remove the rod with drawer to remove the old grease,
clean the drawer and put it back in place;
3.
With the motor running, inject the amount of grease
specified on the rolling bearing nameplate by means of
a manual grease gun;
4.
The excess of grease comes out through the bearing
lower drain and is deposited in the drawer;
5.
Leave the motor running long enough for the grease
excess to drain;
6.
Remove the excess of grease, by pulling the drawer
rod and cleaning the drawer. This procedure must be
repeated as many times as necessary until the drawer
no longer retains grease;
7.
Inspect the bearing temperature to ensure that there
was no significant change.
7.10.1.4
Type and amount of grease
The relubrication of the bearings must always be done
with the original grease, specified on the bearing
nameplate and in the documentation of the motor.
ATTENTION
WEG does not recommend the use of
greases different from the motor original
grease.
It is important to perform a correct lubrication, i.e., to
apply the correct grease and in the proper quantity,
because either poor or excessive lubrication will damage
the rolling bearings.
Excessive amount of grease cause temperature increase,
due to the great resistance it offers to the movement of
the bearing rotating parts. Consequently, due to the
heating, the grease can completely lose its lubricating
characteristics.
