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MOTOR ENCLOSURES
The enclosure type is determined by whether the motor is cooled
by air moving through it, or by convection to the ambient air
around it, or by air moving over it. CONSTANT TORQUE
SPEED RANGE (CTSR) is a thermal consideration. The constant
torque speed range is the range of speeds (based on base
speed) over which the motor will run at full load without
overheating or de-rating. De-rating the motor beyond its speed
range does not mean it will not put out full torque. It means the
motor cannot thermally support full torque output continuously.
DPFG -- DRIP PROOF, FULLY GUARDED
The drip proof fully guarded motor moves air through the motor
by means of an internal, shaft driven fan. Louvered covers in the
front and rear of the motor prevent foreign matter from entering
the motor when dropped from above or at an angle of up to 18°
from the vertical. The Constant Torque Speed Range of the
DPFG motor may be 2:1 or 100: 1, depending upon the frame
size.
DPBV -- DRIP PROOF, BLOWER VENTILATED
The drip proof, blower ventilated motor uses forced air through
the motor to cool it. The blower is generally mounted at the rear of
the motor (at the non-drive end) and the forced air is exhausted
out the front of the motor. The blower is separately powered. The
CTSR is normally 100:1 or better.
TENV -- TOTALLY ENCLOSED, NON-VENTILATED
The totally enclosed non-ventilated motor is dust-tight with no
openings to the ambient air. The motor is cooled by natural
convection and radiation. The CTSR of the TENV motor is
100:1 or greater, but the horsepower range is limited to smaller
sizes.
TEFC -- TOTALLY ENCLOSED, FAN COOLED
The totally enclosed fan cooled motor is dust-tight with no
openings to ambient air. A shaft-mounted fan on the non-drive
end of the motor cools the motor. This allows higher horsepowers
than TENV. The CTSR of TEFC motor is 2:1.
TEAO -- TOTALLY ENCLOSED, AIR OVER, OR
TEBC – TOTALLY ENCLOSED, BLOWER COOLED
If a totally enclosed applications requires a wider speed range
and larger horsepowers, the totally enclosed, air over (blower
cooled) motor has a constant speed fan, which blows air over the
motor's external surface to cool it. Since the air volume is constant
with speed, the Constant Torque Speed Range of the TEAO
motor is 100:1.
© copy right 2012 by P O WE R TEC Industrial Motors, Inc
POW ERTEC "F" Series Motor Manual
TEWC -- TOTALLY ENCLOSED, WATER COOLED
For still larger sizes of totally enclosed motors, the totally
enclosed, water cooled motor removes heat by means of a water
jacket. Cooling water, or other liquid, may be used in a closed or
open system. The CTSR is 100:1 or greater.
This list is not a complete listing of all types, nor is the description
complete. For further information on motor enclosures, consult
NEMA Publication No. MG1.
MOTOR COOLING REQUIREMENTS
FORCED AIR COOLING
DPBV and TEAO motors require forced-air cooling, which is
accomplished by a centrifugal blower and AC motor. Separately
Ventilated motors (DPSV) require the user to supply a forced
air stream to cool the motor. Whether supplied by
POW ERTEC or others, the cooling blowers must have
minimum specifications as follows:
FRAME
182T, 184T
213T,215T, 219T
254T,256T
259T, 2512T
287T,288T,2810T,2812T
328T,3211T,3213T
504ATZ, 506ATZ, 508ATZ
Check the motor blower nameplate for the voltage and current
requirements of your blower.
WATER COOLING
Cooling water for TEWC motors must enter the motor at no more
than 40 °C. To maintain a maximum temperature at the water
outlet of 55 °C, the following minimum flow rates must be
maintained for each frame size listed:
FRAME
254T
256T
259TZ
288TZ
2810TZ
2812TZ
328TZ
3211TZ
3213TZ
Other cooling liquids and/or additives may be used. Consult
the factory for the required flow rates.
AIRFLOW
STATIC
BLOWER
CFM
PRESSURE
inches of water
100
0.9
200
1.9
223
1.6
270
2.6
425
4.6
660
4.0
1500
1.1
FLOW RATE (GPM)
0.8
1.3
1.7
1.8
2.2
2.7
3.4
4.0
4.0
SIZE
2
3
3
8
9
10
12
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