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English (US)
12. Maintaining the motor
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.
12.2 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.
12.3 Recommended lubricant
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:
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.
Warning
The grease outlet plug MUST be removed before
adding new grease.
Severity of duty Ambient temperature (max.) Environment Approved types of grease
Standard 104 °F (40 °C) Clean, little corrosion 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).
Severe 122 °F (50 °C) Moderate dirt, corrosion
Extreme
> 122 °F (50 °C) or class H
insulation
Severe dirt, abrasive dust,
corrosion
NEMA (IEC) frame size
Service intervals [hours]
Weight of grease
[oz (grams)]
Volume of grease
[in
3
(teaspoons)]
Standard duty Severe duty Extreme duty
Up to and incl. 210 (132) 5500 2750 550 0.30 (8.4) 0.6 (2)
Over 210 up to and incl.
280 (180)
3600 1800 360 0.61 (17.4) 1.2 (3.9)
Over 280 up to and incl.
360 (225)
2200 1100 220 0.81 (23.1) 1.5 (5.2)
Over 360 (225) 2200 1100 220 2.12 (60.0) 4.1 (13.4)
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