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Lubrication Information

Marathon Electric Lubrication Procedures

Marathon Lubrication Information

Motors are properly lubricated at the time of manufacture. It is not necessary to lubricate at the time of installation unless the motor has been in storage for a period of 12 months or longer (refer to lubrication procedure that follows).

Lubrication Procedures

  1. Stop Motor. Disconnect and lock out of service
  2. Remove contaminants from grease inlet area
  3. Remove filler and drain plugs
  4. Check filler and drain holes for blockage and clean as necessary
  5. Add proper type and amount of grease. See the Relubrication Time Intervals table for service schedule and Relubrication Amounts table for volume of grease required.
  6. Wipe off excess grease and replace filler and drain plugs (see following warning).
  7. Motor is ready for operation.

Warning: if motor is nameplated for hazardous locations, do not run motor without all of the grease or drain plugs installed.

Relubrication Time Interval

For motors with regreasing provisions.

Service Condition NEMA Frame Size
140-180 210-360 400-510
1800 RPM and less Over 1800 RPM 1800 RPM and less Over 1800 RPM 1800 RPM and less Over 1800 RPM
Standard 3 yrs 6 months 2 yrs 6 months 1 yr. 3 months
Severe 1 yr. 3 months 1 yr. 3 months 6 months 1 month
Seasonal See Note 2









  1. For motors nameplated as “Belted Duty Only,” divide the above intervals by 3
  2. Lubricate at the beginning of the season, then follow service schedule above

Seasonal Service: The motor remains idle for a period of six months or more
Standard Service: Up to 16 hours of operation per day, indoors, 100 ºF maximum ambient
Severe Service: Greater than 16 hours of operation per day. Continuous operation under high ambient temperatures (100 to 150 ºF) and/or any of the following: dirty, moist locations; high vibration (above NEMA standards), heavy shock loading, or where shaft extension is hot.

Relubrication Amounts

NEMA Frame Size Volume cu. in. (fluid oz.)
140 .25 (.14)
180 .50 (.28)
210 .75 (.42)
250 1.00 (.55)
280 1.25 (.69)
320 1.50 (.83)
360 1.75 (.97)
400 2.25 (1.2)
440 2.75 (1.5)
500 3.00 (1.7)



  1. Disconnect power before working on motor or driven equipment
  2. Motors with automatic thermal protections will automatically restart when the protector temperature drops sufficiently. Do not use motors with automatic thermal protectors in applications where automatic restart with be hazardous to personnel or equipment.
  3. Motors with manual thermal protectors may start unexpectedly after protector trips. If manual protector trips, disconnect motor from power line. After protector cools (five minutes or more) it can be reset and power may be applied to motor.
  4. Discharge all capacitors before service motor
  5. Always keep hands and clothing away from moving parts
  6. Never attempt to measure the temperature rise of a motor by touch. Temperature rise must be measured by thermometer, resistance, imbedded detector, or thermocouple
  7. Electrical repairs should be performed by trained and qualified personnel only.
  8. Failure to follow instructions and safe electrical procedures could result in serious injury or death.
  9. If safety guards are required, be sure the guards are in use.

If trouble is experienced in the operation
of the motor, make sure that:

  1. The bearings are in good condition and operating properly
  2. There is no mechanical obstruction to prevent rotation in the motor or in the driven load
  3. The air gap is uniform (Consult manufacture for specifications).
  4. All bolts and nuts are tightened securely
  5. Proper connection to drive machine or load has been made.

In checking for electrical troubles, be sure that:

  1. the line voltage and frequency correspond to the voltage and frequency stamped on the nameplate of the motor.
  2. The voltage is actually available at motor intervals
  3. The fuses and other protective devices are in proper condition
  4. All connections and contacts are properly made in the circuits between the control apparatus and motor.