There are several types of cooling system for DC Motor. One need to choose cooling system carefully. Some are described below.
Dripproof Fully Guarded Self Ventilated (DPFG):
The DPFGmotor is self ventilated, with no external cooling. Open dripproof motorsare modifiable to separately vented enclosures.They are suitable to deliver 100% rated torque down to 60% of base speed.
Dripproof Fully Guarded Blower Ventilated (DPBV):
This type ofenclosure has a blower, with or without filter, as a standard option. Theblower is mounted on the commutator end of the motor toprovide constant air flow CFM (ft.1/min.) for cooling. DC motors with blowerventilation deliver 100% of rated torque downto 5% of the motor’s base speed.
Dripproof Separately Ventilated (DPPV or DPSV) :
The dripproof, separatelyventilated DC motor uses ducted in air, which must provide the proper CFM inorder to cool the motor. This type ofmachine is capable of delivering 100% of rated torque down to 5% of its basespeed.
Totally Enclosed Separately Ventilated(TEPV or TESV):
The totally enclosed separately ventilated motor has airflow ducted in and ducted out. This air flow must provide the proper CFM to cool the motor. It is capable ofdelivering 100% of its rated torque down to 5% of base speed.
TotallyEnclosed Non-Ventilated (TENV):
The TENV machine hasno external cooling, but uses an internal fan to move air within the motor.These enclosures are designed to deliver100% of rated torque down to 5% of its base speed.
TotallyEnclosed Air Over (TEAO):
The totally enclosedair over motor has a blower mounted piggyback on top of the motor frame. Thisallows for constant air flow on the motorframe’s external surface. DC motors in totally enclosed air over enclosuresdeliver 100% rated torque down to 10% of base speed.
Totally Enclosed Fan Cooled (TEFC):
The TEFC machine hasan external fan mounted on the commutator end shaft. Air flow varies with the speed of the motor and is therefore notsuited for low RPM applications.
Totally Enclosed Unit Cooled (TEUC) Air-to-Air Heat Exchanger:
These units consistof an air-to-air heat exchanger that is cooled by an external air blowerassembly. The external air blower assembly draws airthough the air inlet. An internal air blower assembly circulates the internalcooled air through the motor.
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2 comments:
what influeance do airflow in a totaly enclosed D.C motor have on the brush performance.
That's a bit tricky question. As brush performance is depend on the commutator surface temperature. Airflow makes commutator as well as the motor temperature under control. [for medium environment]
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