How to Read a Marathon Industrial Motor Nameplate

How to Read an Industrial Motor Nameplate

Understanding industrial motor nameplate data is essential when selecting motor replacements. The nameplate typically contains most of the key information required to identify a suitable replacement. Being able to interpret the nameplate and understand its abbreviations ensures you choose the right motor for the job.

It's also good practice to record all nameplate details, as this can save time and prevent confusion in the future. Over time, exposure to dirt, rust, and other elements may obscure the nameplate, making it difficult to read when you need it most. Proper documentation now can make replacements much easier later.

 

  1. DATE CODE - The month and year manufactured
  2. MODEL - The ID number
  3. SER. - Serial number
  4. PART NO. - Customer part number
  5. FRAME - The size & mounting
  6. ENCL - Enclosure (e.g. TEFC)
  7. PH - Electrical phase usually 1 or 3
  8. IP - International Protection rating of the enclosure to solids and liquids as defined by IEC 60034-5 and NEMA MG1
  9. IC - Inherit Cooling
  10. MTG. - Mountinge
  11. DES. - Code by NEMA®* or IEC®*
  12. CODE – NEMA locked-rotor KVA 13. INS CL - Insulation class
  13. RISE - The temperature rise over ambient expressed in ºC when the motor operates at nameplated HP or KW
  14. S.F. - Percentage of the rated horsepower the motor can safely operate at Example: 1.15 SF (115% of rated HP)
  15. MAX AMB - The allowable surrounding air temperature
  16. ALTITUDE - The allowable altitude
  17. VOLTS - Voltage rating of the motor at the operating frequency
  18. HZ - Input frequency of the power supply, usually 50 or 60 HZ
  19. HP - Rated horsepower the motor will produce
  20. KW - Rated output in watts
  21. PF / COS - Power Factor / Cosine is the ratio of actual power to the apparent power
  22. RPM - Full load speed at rated frequency
  23. NOM EFF - Average efficiency
  24. F.L. AMPS - The rated load current expressed in amps at nameplated horsepower with nameplate voltage and frequency
  25. DUTY - Time rating under load
  26. TYPE - Electrical type
  27. SHAFT END BEARING - Manufacturer drive end bearing number
  28. OPP. END BEARING - Manufacturer opposite drive end bearing number
  29. MTH/YR MFG. - Month and year the motor was manufactured
  30. WT/LBS - Motor weight in pounds
  31. WT/KG - Motor weight in kilograms