ODP and TEFC Electric Motors

Motor type is an important but often overlooked feature when selecting a centrifugal electric water pump. Heat and contamination are the two main factors that cause a centrifugal pump's electric motor to decrease in performance, or worse, fail. The ways in which a electric motor is protected against heat and contamination make a big difference in the life span of your equipment. 

There are seven types of NEMA standard motors. For the sake of our conversation, we're going to focus on the two most popular types: 

1. Open Drip Proof (ODP)

2. Totally Enclosed Fan Cooled (TEFC)

An ODP motor's housing features stamped vent openings to create airflow around the windings, which in turn cools the motor. The vents are strategically placed around the pump to try to direct water or moisture from landing on the windings of the motor. This design of an electric motor is fine for air flow in and around the motor, but does not keep dust and contaminants from getting around the windings which can cause the motor to overheat or fail. An ODP motor is less expensive to purchase and is recommended for use in more sterile environments that are free from moisture, dust, and other contaminants. 

TEFC motors have an enclosure that keeps oustide air from circulating inside of the motor. An external fan is mounted outside the frame to blow air around the enclosure to keep the windings cool. This type of motor is recommended for most industrial applications. A TEFC motor is effective in protecting the electric motor against moisture and contaminants that can degrade the windings. For outdoor use, we recommend an additional protective cover be used to keep rain and debris from falling directly on the motor. 

Your electric motor type should match the environment in which the water pump will be operating. Over the years, the industry has transitioned to TEFC motors since the design is more successful in protecting the motor, which means longer life for your pump at a reasonable premium in cost – about $50.00 a pump. 

At Absolute Water Pumps, we want to help you get the right pump with the right motor type for your application. We carry hundreds of quality AMT Gorman-Rupp electric pump models in both ODP and TEFC motor types.