Electrical enclosure applications

Pressure detection shall be used for closed enclosure applications. Threshold detectors provide an electric signal when a preset overpressure is exceeded. Dynamic detectors provide an electric signal to the control and indicating equipment (CIE). Typically they have both rate-of-rise and pressure threshold triggering points that can be configured specifically to the application conditions. Although this type of detector minimizes spurious activation of the isolation system (due to pressure fluctuations other than explosion pressure rise), care shall be taken to set up such detectors to meet appropriate detection response criteria for the particular application and protected enclosure geometry. 

Today s vinyl moulding compounds are successfully meeting the combined challenges of physical properties, appearance, processability, and cost requirements in a variety of specialty injection moulding applications such as appliance parts, business equipment, and electrical enclosures. One of the major reasons why vinyl materials are so versatile is that the PVC resins on which they are based can be easily modified with a variety of additives to tailor the particular performance features of the compounds to their intended applications. Determination of an appropriate combination of PVC resin and additives to produce an effective and cost-competitive compound,... 

To reduce the likelihood that a system will experience fire, many Companies write UL VO listings into contract requirements when purchasing electrical enclosures. The UL VO listing is a stringent flammability test for elastomers. But just because a material can serve in high temperature applications, does not automatically guarantee that it has adequate flammability resistance to qualify for the UL 94 VO rating. A case in point is the various brands of silicone. 

Electric-motor application for the plant engineer is the common-sense matching of load requirements with motor characteristics. Motor types, styles, sizes, mountings, and enclosures vary greatly. So the first step in using electric motors correctly is to understand them and the terminology the motor industry uses to describe them. 

Electrical Applications. Plastics are used for electrical insulation, conduit and enclosures, lighting fixtures, and mechanical devices. The most widely used plastic for wire and cable insulation is flexible, plasticized PVC, which constitutes well over half the market in insulating wires for buildings, automobiles, appHances, and power and control lines. Polyethylene is also a factor. Higher performance plastics such as nylon and fluoropolymers also play a smaller role in this area. 

Although transformers suitable for other industrial installations are generally suitable for producing applications, certain options may be desirable— primarily due to environmental considerations. At locations subject to harsh environmental conditions, and particularly at locations subject to washdown with high-pressure hoses, non-ventilated enclosures are desirable, if not necessary. Likewise, at locations subjected to salt water and salt-laden air, it often is desirable to specify copper windings and lead wires. Most manufacturers provide standard units with aluminum windings and lead wires. Even if aluminum coils are used, it is almost always desirable to require stranded copper lead wires. This will lessen corrosion and loose terminal problems when transformers arc interconnected to the facility electrical system with copper conductors. If the transformers are to be installed outdoors in corrosive environments, cases should be of corrosion-resistant material (e.g., stainless steel) or be provided with an exterior coating suitable for the location. 

Energy Applications Desiccant cooling is a means for more efficiently providing air conditioning for enclosures such as supermarkets, ice rinks, hotels, and hospitals. Adsorbers are integrated with evaporative and electric vapor compression cooling equipment into an overall... 

These enclosures are designed to meet the applicable requirements of the National Electrical Code (NFPA 70) for Class I Groups A, B, C, or D hazardous locations that may be in effect. In this type of equipment, the circuit interruption occurs in air. 

These enclosures are designed to the applications requirements of the National Electrical Code (NFPA 70),... 

There are perhaps hundreds of miscellaneous unsaturated polyester resin construction applications. These would include window frames, doors, cabinet enclosures, electrical boxes, etc. In addition, recent developments bode well for unsaturated polyesters in construction markets. Concrete rebar, bridge construction and general infrastructure repair are examples of growing construction applications. 

Water mist systems are intended for rapid suppression of fires using water discharged into completely enclosed limited volume spaces. Water mist systems are desirable for spaces where the amount of water that can be stored or that can be discharged is limited. In addition, their application and effectiveness for flammable liquid storage facilities and electrical equipment spaces continues to be investigated with optimistic results. Water mist systems are also used for gas turbine enclosure protection. 

In industrial applications it is not uncommon that the thermocouple must be coupled to the readout instrument or controller by a long length of wire, perhaps hundreds of feet. It is obvious from the differential nature of the thermocouple that, to avoid unwanted junctions, extension wire be of the same type, eg, for a J thermocouple the extension must be type J. Where the thermocouple is of a noble or exotic material, the cost of identical lead wire may be prohibitive manufacturers of extension wire may suggest compromises which are less cosdy. Junctions between the thermocouple leads and the extension wire should be made in an isothermal environment. The wire and junctions must have the same electrical integrity as the thermocouple junction. Because the emf is low, enclosure in a shield or grounded conduit should be considered. 

A furnace is a device (enclosure) for generating controlled heat with the objective of performing work. In fossil-fuel furnaces, the work application may be direct (eg, rotary kilns) or indirect (eg, plants for electric power generation). The furnace chamber is either cooled (waterwall enclosure) or not cooled (refractory lining). In tbis article, furnaces related to metallurgy such as blast furnaces are excluded because they are covered under associated topics (see... 

Applications. The kinds of motors that are being used successfully with particular kinds of. chemical process equipment are identified in Table 4.1. As many as five kinds of AC motors are shown in some instances. The choice may be influenced by economic considerations or local experience or personal preference. In this area, the process engineer is well advised to enlist help from electrical experts. A checklist of basic data that a supplier of a motor must know is in Table 4.2. The kind of enclosure may be specified on the last line, operating conditions. 

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