Large Industrial Electric Motor Specialists

What is a TEFC Motor?

Table of Contents

A totally enclosed fan cooled (TEFC) motor is a type of electric motor that uses a fan mounted on the rear side to blow air over the motor to provide cooling. TEFC motors are completely enclosed in a rugged housing which prevents dust, water, and other contaminants from entering the motor.

How TEFC Motors Work

The fan mounted on the rear of the motor pulls air in through openings and blows it over the motor windings to provide cooling. The enclosure keeps the internal components clean for optimal performance and prevents debris from interfering with operation.

TEFC motors are available in single and three-phase power configurations. The windings are immersed in a resin to provide electrical insulation. There are no external vent openings in a TEFC motor, so the enclosure maintains IP54 or IP55 ingress protection ratings against dust and splashing water.

Benefits of TEFC Motors

Totally enclosed fan cooled motors provide several advantages compared to open style motors

  • Protection from contaminants – The rugged housing prevents dirt, dust, moisture, and chemicals from damaging the internal components. This allows TEFC motors to operate reliably in demanding industrial environments.
  • Cool running – The fan circulation allows TEFC motors to run cooler than open frame motors. This equates to better efficiency, longer winding life, and more reliable operation.
ge quantum tefc motor
  • Quiet operation – With no openings, TEFC motors operate with less noise than open ventilated motors.
  • Versatile mounting – TEFC motors can be mounted horizontally or vertically without impacting ventilation. This provides flexibility for installation.
  • Reduce maintenance – By protecting the internal components from contamination, TEFC motors require less maintenance and have a longer service life.

Common Applications of TEFC Motors

Totally enclosed fan cooled motors are widely used in industrial and commercial applications where dust, vapors, moisture, or chemical fumes are present. Typical applications include:

  • Pumps, fans, blowers, and air compressors
  • Conveyor systems and material handling equipment
  • Machine tools like mills, lathes, grinders
  • Packaging and food processing machinery
  • Woodworking and textile mill equipment
  • HVAC equipment like fans and air handlers
  • Mining and oil drilling equipment

TEFC motors are the workhorse of manufacturing facilities, plants, and warehouses due to their rugged dependable construction. They are also popular for outdoor use since the enclosure protects the motor from weather elements.

TEFC Motor Enclosures

The housings used on TEFC motors are precision engineered to protect internal components while allowing proper air circulation. Typical enclosures include:

  • Cast iron – Offers excellent protection with low cost. Used for general industrial applications.
  • Rolled steel – Thinner but stronger than cast iron. Used for high vibration applications.
  • Stainless steel – Withstands corrosive environments. Used in chemical, food, and pharmaceutical plants.
  • Aluminum – Lightweight housing for fans, blowers, and pumps.
  • Explosion proof – Designed to contain sparks and explosions. Used where flammable vapors are present.

Gaskets, sealed seams, and bolted access covers prevent moisture and contaminants from entering the motor. High quality bearings ensure long service life.

Where Can You Buy a TEFC Motor?

TEFC motors come in all types of classifications and models. Check out our TEFC motors for sale page to see some of the different pricing options that Heartland Motors has, in addition to our fast delivery times. Buying a TEFC motor doesn’t have to be hard, or confusing. We make it as painless as possible for you.

TEFC vs TEAO Motors

TEAO motors differ from TEFC motors in that they use their own frame surface for heat dissipation rather than depending on a fan for cooling. TEAO (totally enclosed air over) motors have no fan and rely on the motor housing for convection cooling.

TEAO motors are also totally enclosed, but are not as widely used as TEFC motors. They see most use in applications with very high contamination levels where the lack of a fan prevents buildup on the windings. They are also used in explosive environments since they contain no sparks from brushes. TEAO motors run at higher temperatures than TEFC equivalents.

ODP vs. Totally Enclosed Fan Cooled

Here is a comparison of ODP (open drip proof) and TEFC (totally enclosed fan cooled) electric motors:


  • ODP motors have openings that allow air circulation but also provide pathways for contaminants to enter.
  • TEFC motors are completely enclosed to prevent dirt, moisture, and debris from getting inside.


  • ODP motors rely on external airflow across the frame for cooling.
  • TEFC motors use an internal fan to circulate air through the enclosure.

Environmental protection:

  • ODP motors have more exposed components and only basic splash protection.
  • TEFC motors can operate in wet, dirty, corrosive environments thanks to sealed housing.

Noise levels:

  • ODP motors tend to be louder due to open ventilation slots.
  • TEFC motors run quieter because of closed enclosure.


  • ODP motors lose less energy to friction so can be slightly more efficient.
  • TEFC motors work harder to pull air through enclosure so operate warmer.


  • ODP motors require more frequent internal cleaning and lubrication.
  • TEFC motors are mostly sealed so need less maintenance.


  • ODP motors work well indoors where conditions are clean and ventilated.
  • TEFC motors handle locations with water, chemicals, dust, fibers, and outdoor weather.


  • ODP motors are more economical for general purpose applications.
  • TEFC motors cost more but last longer with reduced maintenance.

Essentially, TEFC motors provide greater protection and suitability for harsh environments, while ODP motors offer better ventilation and efficiency for clean indoor use.

Common Questions about TEFC Motors

This section will provide an overview of common questions in relation to how TEFC motors work, along with answers. Read on to learn more about sizing, applications, maintenance, and other key factors to consider when selecting and operating totally enclosed fan cooled motors.

What size TEFC motor do I need?

The required motor size depends on your load conditions including the torque and horsepower requirements. Consult the equipment data plate or a sizing chart based on your drive system. Oversizing can cause inefficiency while undersizing can damage the motor.

How long do TEFC motors last?

With proper installation and maintenance, a TEFC motor can operate reliably for 15-20 years or more. Bearings typically determine the lifespan of an AC motor. Re-lubricatable bearings can extend the service life further to 30+ years.

Can you control the speed of a TEFC motor?

Yes, you can control a TEFC motor’s speed using a variable frequency drive (VFD). By varying the input frequency to the motor, VFDs provide easy speed control for applications like conveyors, machine tools, and HVAC systems.

What maintenance is required on TEFC motors?

TEFC motors are designed to be maintenance-free apart from occasional re-lubrication after many years of service. However, you should periodically check the motor for excessive vibrations, dirt buildup, and overheating issues. The fan, bearings, and other components can be accessed by removing the rear cover.

Can you run a TEFC motor outdoors?

Yes, the rugged enclosed design allows TEFC motors to withstand outdoor weather elements. Ensure the enclosure has an appropriate NEMA rating for the environment. Use moisture-resistant coatings and mount the motor to prevent water pooling on the fan cover. Provide shields against direct sunlight exposure.

Summary – Totally Enclosed Fan Cooled Motors Explained

A totally enclosed fan cooled motor provides excellent protection for the internal components while maintaining proper cooling. The airtight design allows TEFC motors to operate reliably for years in challenging industrial and outdoor environments. Their versatile construction makes TEFC motors the go-to choice for demanding applications that involve dirt, vapors, moisture, or chemical contaminants. With proper sizing, installation, and maintenance, TEFC motors will deliver many years of trouble-free operation.

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