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7 Most Common Motor Enclosure Types

Defined By NEMA Standards

Important role of enclosure

The enclosure of the motormust protect the windings, bearings, and other mechanical parts from

moisture, chemicals, mechanical damageand abrasion from grit.

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NEMA standards MG1-1.25 through 1.27define more than 20 types of enclosures under the

categories of open machines, totally enclosed machines, and machines with encapsulated or

sealed windings.

The 7 most common tyes of enclosures are!

1. Open Drip roof !OD"

Premium Efficient Super-E motor with Open rip Proof

!OP" construction by #$%O&

$llows air to circulate through the windings for cooling, but pre'ent drops of li(uid from falling

into motor within a )* degree angle from 'ertical. Typically used for indoor alications inrelati"ely clean, dry locations.

#. Totally Enclosed $an Cooled !TE$C"

+eg E$ Premium Efficiency - Three Phase TE/otors

Pre'ents the free echange of air between the inside and outside of the frame, but does not ma1ethe frame completely air tight. $ fan is attached to the shaft and pushes air o'er the frame during

its operation to help in the cooling process.

The ribbed frameis designed to increase the surface area for cooling purposes.

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The TEFC style enclosure is the most versatile of all.It is used on pumps,fans, compressors, general industrial belt driveand direct connected equipment.

Total Enclosed $an Cooled %s Open Drip roof !TE$C %s OD"

&. Totally Enclosed Non'(entilated !TEN("

$TO / otor, P, TE3, )45 6P, )700 rpm,283/

Similar to a TE/, but has no cooling fanand relies on con'ention for cooling. o 'ent

openings, tightly enclosed to pre'ent the free echange of air, but not airtight.

These are suitable for uses which are eposed to dirt or dampness, but not "ery moist orha#ardous $e%losi"e& locations.

). Totally Enclosed Air O%er !TEAO"

9S otors - &efrigeration uty TE$O otor, )42 6P,

5-Phase, ))80 &P otor

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ust-tight fan andblower duty motorsdesigned for shaft mounted fans or belt dri'en fans. The

motor must be mounted within the airflow of the fan.

*. Totally Enclosed +as, do-n !TE+D"

#aldor:s +ashdown uty otor for food processing,

pac1aging, pharmaceuticals, or applications where motors are regularly eposed to high pressurewash down.

esigned to 'ithstand high ressure 'ash-do'nsor other high humidity or wet en'ironments.

$'ailable on TE$O, TE/ and E3 enclosures totally enclosed, hostile and se'ere en'ironment

motors;

(esigned for use in e%tremely moist or chemical en"ironments) but not for ha#ardous

locations.

. E/plosion'proof enclosures !E0"

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S

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otor 5-Phase, * 6P - to Power ans,#lowers, Pumps or $ir /ompressors in $reas That eet the ational Electrical /ode for

6a=ardous %ocations

6a=ardous location motorapplications are classified by the type of ha=ardous en'ironment

present, the characteristics of the specific material creating the ha=ard, the probability of

eposure to the en'ironment, and the maimum temperature le'el that is considered safe for the

substance creating the ha=ard.

The format used to define this information is a class, group, di'ision and temperature

code structure as defined by theNational Electric ,ode $NA-7/&.

The follo'ing ha#ardous locations are defined!

1" CASS I

5roup A6$cetylene

5roup B6#utadiene, ethylene oide, hydrogen, propylene oide, manufactured gases

containing more than 50ydrogen by 'olume.

5roup C6$cetaldehyde, cyclopropane, diethyl ether, ethylene.

5roup D6$cetone, acrylonitrile, ammonia, ben=ene, butane, ethanol, ethylene

dichloride, gasoline, heane, isoprene, methane !natural gas", methanol, naphtha,

propane, propylene, styrene, toluene, 'inyl acetate, 'inyl chloride, ylene.

#" CASS II

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5roup E6$luminum, magnesium, and other metal dusts withsimilar characteristics.

5roup $6/arbon blac1, co1e or coaldust.

5roup 56lour, starch orgrain dust.

&" CASS III

Easily ignitable fibers,such asrayon, cotton, sisal, hemp, cocoa fiber, oa1um, ecelsior

and other materials of similar nature.

The NEMA enclosure descrition is similar to the 0E, 0nde% of rotection $0& code.The E$ designations are more descripti'e and general, whereas the

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Open and Enclosed Types

A- Open Enclosure

open drip proof (ODP) enclosure

pen enclosures permit cooling air to flow through the motor. ne type of openenclosure is the open drip proof ("#) enclosure. This enclosure has $ents that allow

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for air flow. %an blades attached to the rotor mo$e air through the motor when therotor is turning. The $ents are positioned so that li&uids and solids falling from abo$eat angles up to from $ertical cannot enter the interior of the motor when themotor is mounted on a hori*ontal surface. +hen the motor is mounted on a $erticalsurface, such as a wall or panel, a special co$er may be needed. "# enclosures

should be used in en$ironments free from contaminates.

B- Totally enclosed Enclosure

This category will include the following three types:

Totally !nclosed on-entilated !nclosure.

Totally !nclosed %an-/ooled !nclosure.

!0plosion-#roof !nclosure.

a- Totally Enclosed Non-Ventilated Enclosure (TENV)

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Totally Enclosed Non-Ventilated Enclosure (TENV)

In some applications, the air surrounding the motor contains corrosi$e or harmfulelements which can damage the internal parts of a motor. A totally enclosed non-$entilated (T!) motor enclosure limits the flow of air into the motor, but is notairtight. 1owe$er, a seal at the point where the shaft passes through the housingpre$ents water, dust, and other foreign matter from entering the motor along theshaft.

2ost T! motors are fractional horsepower. 1owe$er, integral horsepower T!motors are used for special applications. The absence of $entilating openings meansthat all the heat from inside the motor must dissipate through the enclosure byconduction. These larger horsepower T! motors ha$e an enclosure that is hea$ilyribbed to help dissipate heat more &uickly. T! motors can be used indoors oroutdoors.

b- Totally Enclosed Fan-Cooled Enclosure (TEFC)

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Totally Enclosed Fan-Cooled Enclosure (TEFC)

A totally enclosed fan-cooled (T!%/) motor is similar to a T! motor, but has ane0ternal fan mounted opposite the dri$e end of the motor. The fan blows air o$er themotor's e0terior for additional cooling. The fan is co$ered by a shroud to pre$entanyone from touching it. T!%/ motors can be used in dirty, moist, or mildly corrosi$een$ironments.

c- Eplosion-Proof Enclosure (!P)

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Eplosion-Proof Enclosure (!P)

1a*ardous duty applications are commonly found in chemical processing,

mining, foundry, pulp and paper, waste management, and petrochemicalindustries. In these applications, motors ha$e to comply with the strictestsafety standards for the protection of life, machines and the en$ironment. Thisoften re&uires use of e0plosion proof (3#) motors.

An 3# motor is similar in appearance to a T!%/ motor, howe$er, most 3#

enclosures are cast iron.

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"i$ision I locations normally ha$e ha*ardous materials present in the

atmosphere.

"i$ision II locations may ha$e ha*ardous material present in the atmosphere

under abnormal conditions.

4ocations defined as ha*ardous, are further defined by the class and group of

ha*ard. %or e0ample,

- /lass I, 5roups A through " ha$e gases or $apors present.

- /lass II, 5roups !, %, and 5 ha$e flammable dust, such as coke or grain dust.

- /lass III is not di$ided into groups. This class in$ol$es ignitable fibers and lint.