Motor Enclosure 역할
First, the enclosure protects the motor windings, a critical component, from harmful contaminants in the outside environment like water, dust and high temperature while efficiently cooling and reducing motor noise.
Motor Enclosure 중요성
The enclosure is one of the main factors in determining motor frame size, which may impact the motor cost and the pump system design.
Motor Enclosure Type
When it comes to motor enclosures, there are many options. National Electrical Manufacturers Association (NEMA) standard MG1-2016 defines several different types of common motor enclosures.
(ODP, WPII, TEWAC and TEAAC) for largeand medium-size electric motors (3,000 horsepower [hp] or larger)
Enclosure Types
ODP (Open Drip Proof, IC01, IP12)
Cooling method: The surrounding outside air is drawn into the motor top mounted enclosure to cool the whole motor body, including rotor and stator windings.
Advantages: ODP enclosures are considered the least expensive, simplest structures among top-hat-type enclosures. Stators and rotor windings are cooled by outside air, keeping the frame size relatively small. 구조 간단, 가격이 저렴
Disadvantages: The open enclosure design results in a high noise level compared to other enclosure types. It is also difficult to apply noise abatement techniques because the noise from the internal shaft-mounted fans reaches the outside. This type is not applicable for Division 1 hazardous areas. 높은 소음, 외부 이물질 유입 가능성
Recommendations: Recommend ODP for clean and well-ventilated indoor areas only. Not suitable for outdoor or corrosive/ dust areas. 깨끗한 내부 환경에서만 가능, 외부나 먼지가 심한 곳은 적절치 않음
WPII (Weather Protected Type II, IC01, IP23/24)
Cooling method: The cooling method is similar to ODP. However, WP II offers better protection against external dust, water and objects.
Advantages: The WPII enclosure is designed for outdoor use. However, it is also suitable in a well-ventilated indoor location.
Disadvantages: Like an ODP enclosure, the high noise can be an issue. If used in a dusty area, the filter can clog easily, causing the motor to trip. This type is not applicable for Division 1 areas.
TEWAC (Totally Enclosed Water to Air Cooled, IC81W, IP54/56)
Cooling method: A TEWAC enclosure uses the high heat absorption property of liquids for motor cooling. 물로 쿨링
Advantages: This type of enclosure has the best cooling efficiency and lowest noise compared with other types of enclosures
Disadvantages: Capex/opex cost is the highest among top-hat-type enclosures. Cooling water is always required for a TEWAC enclosure.
Recommendations: A TEWAC design is the best option for large motors when the maximum ambient temperature is high and cooling water is available. It is best for use in a corrosive and dusty area and is suitable for Division 1/Division 2 hazardous areas when properly designed
TEAAC (Totally Enclosed Air to Air Cooled, IC611, IP54/56)
Cooling method: A TEAAC enclosure is equipped with an external fan that blows surrounding ambient air into the motor frame’s heat exchanger tubes. The motor heat exchanger is designed to efficiently transfer internal motor heat to the surrounding air. (외부 FAN으로 쿨링)
Advantages: A TEAAC enclosure does not require cooling water at the site. As the frame is totally enclosed, this option is suitable for dusty /corrosive/humid/ salty areas. The noise abatement technique is easy to apply. 쿨링워터 불필요
Disadvantages: This enclosure’s frame size is usually one or two sizes larger than TEWAC or WPII when the other specs are the same. The initial cost is the highest, and there is some limit in the rated power range. Noise level is higher than a TEWAC (모터 사이즈가 커짐)
Recommendations: A TEAAC enclosure is recommended when the maximum ambient temperature is not high and cooling water is not available at the site.
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