How to Read a NEMA Electric Motor Nameplate

Motor nameplates contain important information about the electric motor that would be difficult to find anywhere else. Factors such as electric motor manufacturing companies using different nameplate formats, dirty and damaged nameplates that obscure information and strange codes and abbreviations on the nameplate make reading them a challenge. This information is critical when performing any sort of electric motor service. Here are a few of the most common identifiers that you will find on most NEMA electric motor nameplates.

Example of a nameplate for an electric motor service in Knoxville, TN

NEMA Electric Motor Nameplate – Required Information

Most electric motors manufactured after 2007 are required to meet standards established by the National Electrical Manufacturers Association. NEMA helped create the provisions to improve electric motor efficiency to reduce electrical consumption and pollution as part of the Energy Independence and Security Act of 2007 (EISA). NEMA electric motors require the following information on the nameplate:

  • CODE – This is a locked rotor kVA per horsepower identifier using the letters A through V.
  • DES or DESIGN – This letter, which defines the design of the motor by NEMA, describes the four motor designs (A, B, C, and D) by its torque and current characteristics.
  • DUTY or TIME RATING – This information identifies how long (usually in minutes) a motor can run at the rated load speed (RPM). Typically, this value will be CONT (for continuous) which means the motor can run continuously at that speed. Numerical values in this field are usually for motors that run intermittently.
  • ENCL – Enclosure Type – Identifies the enclosure type of the motor by defining characteristics of the motor. See the What is an Ingress Protection Rating for Electric Motors? blog post for more details.
  • FLA – The current drawn by the electric motor when it is fully loaded. Also known as full-load amperes.
  • FR or FRAME – Frame Designation -This is typically a two- or three-digit number followed by one or more letters that identifies important mounting dimensions for the electric motor.
  • HP or kW – Horsepower or Kilowatt output of the motor.
  • HZ – The frequency of the motor expressed in hertz.
  • INS. CLS – Sometimes also listed as INSUL CLASS, is the insulation system designation for the motor winding.
  • MAX AMB – Maximum Ambient Temperature of the air surrounding the motor during operation.
  • PF – Power Factor – This is the result of real power drawn by the motor (in watts) divided by the apparent power (in volt-amperes).
  • PH – Stands for the number of phases of the electric motor.
  • RPM – The Revolutions Per Minute of the electric motor running at a full load.
  • SF – Service Factor – This is the fraction of overloaded power an electric motor can handle for short periods.
  • TYPE – Manufacturers Type – Manufacturers may use the TYPE block to designate a product family or some other qualifier that identifies the motor’s fit or function.
  • VOLTS – The voltage rating for the electric motor running at a full load at optimal performance.

Tekwell Services is an Authorized NEMA Electrical Motor Repair Shop

Tekwell Services has been servicing and repairing NEMA electrical motors since EISA became the law of the land, back in 2007. Give us a call (toll-free) at 1-888-984-4668 or fill out our quick solution form to reach out to a NEMA electrical motor repair expert today.