14.2 Motor lubrication
Electric motors are pre-lubricated from factory and do not require
additional lubrication at start-up. Motors without external grease
zerks have sealed bearings that cannot be re-lubricated. Motors
with grease zerks should only be lubricated with approved types
of grease. Do not over-grease the bearings. Over-greasing will
cause increased bearing heat and can result in bearing or motor
failure. Do not mix oil-based grease and silicon grease in motor
bearings.
Bearing grease will lose its lubricating ability over time. The
lubricating ability of a grease depends primarily on the type of
grease, the size of the bearings, the speed at which the bearings
operate and the severity of the operating conditions.
Good results can be obtained if the following recommendations
are used in your maintenance program. It should also be noted
that multistage pumps, pumps running to the left of the
performance curve, and certain pump ranges may have higher
thrust loads. Pumps with high thrust loads should be greased
according to the next service interval level.
Remove the grease outlet plug before adding new
grease.
14.2.1 Recommended lubricant
Severity of duty
Ambient temperature (max.)
Standard
Severe
> 122 °F (50 °C) or class H
Extreme
14.2.2 Lubricating chart (for motors with grease zerks)
New motors that have been stored for a year or more should be regreased according to the following table:
NEMA (IEC) frame size
Up to and incl. 210 (132)
Over 210 up to and incl. 280 (180)
Over 280 up to and incl. 360 (225)
Over 360 (225)
14.2.3 Lubricating procedure
Keep grease free from dirt to avoid damage to motor
bearings. If the environment is extremely dirty,
contact Grundfos, the motor manufacturer, or an
authorized service center for additional information.
Do not mix dissimilar types of grease.
1. Clean all grease zerks. If the motor does not have grease
zerks, the bearing is sealed and cannot be greased externally.
2. If the motor is equipped with a grease outlet plug, remove it.
This will allow the old grease to be displaced by the new
grease. If the motor is stopped, add the recommended
amount of grease. If the motor is to be lubricated while
running, add a slightly greater quantity of grease.
3. Add grease SLOWLY taking approximately one minute until
new grease appears at the shaft hole in the flange or grease
outlet plug. Never add more than 1 1/2 times the amount of
grease shown in the lubricating chart.
24
104 °F (40 °C)
122 °F (50 °C)
Severe dirt, abrasive dust,
insulation
Service intervals [hours]
Standard duty
Severe duty
5500
2750
3600
1800
2200
1100
2200
1100
Environment
Approved types of grease
Clean, little corrosion
Grundfos ML motors are greased for life,
Moderate dirt, corrosion
or the grease type will be stated on the
nameplate. WEG motors are greased
with Polyrex EM (Exxon Mobile).
corrosion
Weight of grease
Extreme duty
550
360
220
220
If new grease does not appear at the shaft hole or
grease outlet, the outlet passage may be blocked.
Contact Grundfos service center or certified motor
shop.
4. Let motors equipped with a grease outlet plug run for 20
minutes before replacing the plug.
Volume of grease
3
[oz (grams)]
[in
(teaspoons)]
0.30 (8.4)
0.6 (2)
0.61 (17.4)
1.2 (3.9)
0.81 (23.1)
1.5 (5.2)
2.12 (60.0)
4.1 (13.4)