New 2015 ODP Regulations - Why It May Be Time to Go TEFC
Generally speaking, ODP motors have traditionally cost less than their TEFC counterparts, which is one of the main reasons why motor users and machine builders have selected ODP motors over TEFC in the past. Size of the motor can also play a factor in deciding between ODP and TEFC motors, since TEFC motors may have been longer and wider than their ODP versions.
New 2015 efficiency regulations commonly referred to as the “Small Motors Rule,” however, may negate the size and cost advantage of using ODP in lieu of TEFC after the measure takes effect. Now may be a good time for distributors, OEMs and motor users to analyze existing applications that currently rely on small ODP motors, and evaluate the disadvantages of using ODP instead of TEFC.
What are the new ODP Efficiency Regulations?
Effective March 9, 2015, electric motor suppliers will be required to comply with the Department of Energy’s (DOE) energy conservation standard for small ODP electric motors, and will not be allowed to manufacture non-conforming motors for import into the United States. This also includes manufacturers importing machinery that utilize small motors as a component of another piece of non-covered equipment. Motors covered under these expanded efficiency regulations are defined as:
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Posted on: September 18, 2014
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Open Drip Proof (ODP) Enclosures
General Purpose 2-Digit Frame Motors including 42, 48 and 56 Fame Motors (and their IEC equivalents)
Single (1PH) and Three (3PH) Phase Motors
1/4 - 3 HP
3600 - 1800 - 1200 RPM (i.e. 2-5-6 Pole) Motors
ODP motors rely on vents which are used to prevent falling rain from entering the motor enclosure. However, uneven installation or blowing/slanted rain in outdoor and other damp conditions can cause water to enter the motor. While TEFC motor windings are not considered completely sealed against moisture (unless so rated) or submersible, they are substantially more protected against rain, spray and splashes than ODP motors.
While users can mitigate rain contamination by utilizing ODP motors in dry settings, no place in the world is 100% dust-free. Airborne contaminants can leave deposits on ODP motor windings as air is moved directly through the windings via the internally mounted fan and open intake vents on the motor’s end. This can be especially detrimental for single phase motors that have a switch mechanism operating start capacitors located next to the windings, which is easily affected by contaminants – one of the most common causes for failure in outdoor applications. On the other hand, TEFC motors are much more adept at keeping windings dry and dirt-free since these motors do not rely on air drawn in for cooling.
Pests such as mice and insects can wreak havoc in ODP motors which are easily infiltrated. Since TEFC motors are totally enclosed, pests cannot enter the motor and chew through or soil windings.
Whether you choose an ODP or TEFC motor, it is important that the solution fit the application and that the lifetime costs to operate and potential for problems are carefully evaluated. In the end, a slight difference in cost may not be worth the hassle and potential downtime.
Totally Enclosed Fan Cooled (TEFC) motors are not included in this regulation.
How does this effect OEMs using ODP motors covered under this new energy conservation standard?
To put it simply, the new regulation can create motors with much larger footprints, particularly on single phase designs where capacitor-start / induction-run motors may be discontinued in the ODP version. In some cases, a TEFC motor will ultimately be a more cost effective solution and be smaller than the new conforming ODP motor. This may mean that some OEM manufacturers and users may need to make the switch from ODP to TEFC in order to stay in the same motor frame, and forgo the costly application change process.
Without the cost and size advantage of ODP motors, OEMs and motor users may need to consider the disadvantages of using an ODP motor versus the advantages of a TEFC motor: