Maintaining The Motor; Motor Inspection; Motor Lubrication; Recommended Lubricant - Grundfos CR Notice D'installation

12. Maintaining the motor

Warning
Before starting work on the motor, make sure that
all power supplies to the motor have been
switched off and that they cannot be accidentally
switched on. Electric shock can cause serious or
fatal injury. Only qualified personnel should
attempt installation, operation, and maintenance
of this equipment.

12.1 Motor inspection

Inspect the motor approximately every 500 hours of operation or
every three months, whichever occurs first. Keep the motor clean
and the ventilation openings clear.
Go through the following steps during each inspection:
1. Check that the motor is clean. Check that the interior and
exterior of the motor are free of dirt, oil, grease, water, etc.
Oily residue, paper, pulp, textile lint, etc. can accumulate and
block motor ventilation. If the motor is not properly ventilated,
overheating can occur and cause early motor failure.
2. Use an ohmmeter periodically to ensure that the winding
insulation is OK. Record the ohmmeter readings, and
immediately investigate any significant drop in insulation
resistance.
3. Check all electrical connections to be sure that they are
tightened securely.

12.3 Recommended lubricant

Severity of duty Ambient temperature (max.)
Standard
Severe
Extreme

12.4 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
Standard duty
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)
104 °F (40 °C)
122 °F (50 °C)
> 122 °F (50 °C) or class H
insulation
Service intervals [hours]
Severe duty
5500 2750
3600 1800
2200 1100
2200 1100

12.2 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.
Warning
The grease outlet plug MUST be removed before
adding new grease.
Environment
Clean, little corrosion
Moderate dirt, corrosion
Severe dirt, abrasive dust,
corrosion
Weight of grease
[oz (grams)]
Extreme duty
550 0.30 (8.4)
360 0.61 (17.4)
220 0.81 (23.1)
220 2.12 (60.0)
Approved types of grease
Grundfos ML motors are greased
for life, or the grease type will be
stated on the nameplate.
Baldor motors are greased with
Polyrex EM (Exxon Mobile).
Volume of grease
3
[in (teaspoons)]
0.6 (2)
1.2 (3.9)
1.5 (5.2)
4.1 (13.4)
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