Weather protection

Accelerator in Ready-Mix Concrete. Calcium chloride accelerates the set time of concrete giving it a high early strength development. It is not an antifreeze, but by using it duriag cold weather protection can proceed in a timely manner (31—34). In Russia, calcium chloride forms a component of several antifreeze admixtures (33). Reviews of the concerns and possible remedies of calcium chloride corrosion problems in concrete are available (21,35). There is no consensus on what the safe levels of calcium chloride in concrete are. 

Electrical—panels, switches, motors, conduit, wire, fittings, feeders. Weather protection... 

Totally enclosed motors offer the greatest protection against moisture, corrosive vapors, dust, and dirt. Totally enclosed fan-cooled (TEFC) motors are the obvious choice rather than weather-protected below 186.5 kW (250 hp). Their internal and external ventilating air are kept separate external air never gets inside except for the small amount that enters by breathing. 

Enclosed motors with air-to-water coolers cost much less than TEF( motors above 373 kW (5()0 hp) in large svnchronoiis-rnotor ratings, thev cost even less than weather-protected, tvpe II, Large enclosed synchronous machines with coolers for mounting in the motor foundation are frequently supplied at lower cost than motors with integral-mounted coolers. 

Type I A weather-protected Type I machine is an open machine with its ventilating passages so constructed as to minimize the entrance of rain, snow and air-borne panicles to the electrieal parts and having its ventilated openings so constructed as to prevent the passage of a cylindi ical rod 3/4-inch in diameter. 

For larger motors, the next degree of protection is weather-protected, Type I (WPI), which is an open machine with ventilating passages con-stnicted to minimize the entrance of rain, snow, and airborne particles (o the electric parts. 

The force-ventilated type is preferred when a Division 1 classification is necessary. The standard drip-proof enclosure is preferred in Division 2 or in safe locations. For an outdoor installation, serious consideration should be given to using NEMA Type 2 weather-protected enclosures rather than the completely enclosed types. 

Weather-protected, Type II (WP-II), 259 Weight flow control at con,stant speed, 362 Weight flow control with variable stator vanes, 361... 

Classification of environmental conditions. Part 3 Classification of groups of environmental parameters and their seventies. Storage. Superseded BS EN 60721-3-1 1993 Classification of environmental conditions. Part 3 Classification of groups of environmental parameters and their seventies. Transportation. Superseded BS EN 60721-3-2 1993 AMD 1 Classification of environmental conditions. Part 3 Classification of groups of environmental parameters and their seventies. Stationary use at weather protected locations (AMD 9514J dated 15 June 1997. Superseded BS EN 60721-3-3 1993. Previously BS 7527 Section 3.3 1991... 

The pressure relief device used most often in refinery and chemical plant equipment is the spring-loaded, top-guided, high-lift, nozzle-type safety relief valve, which is illustrated in Figure 2. The spring is usually external and enclosed by a bonnet for weather protection, and the bonnet chamber is vented through an internal passage to the valve outlet. 

Fire standing panel framework including a weather protection canopy (against rain and sun). 

Most standard motors are manufactured using non-hygroscopic NEMA Class B insulation. For added protection in an offshore environment, open drip-proof or weather protected motors should be specified with a sealed insulation system. NEMA Class F insulation is also available in most motor sizes and is advisable to provide an improved service factor. 

Temperature Control (Manual) (Automatic). Instruments Controls (Weather Protected) (Explosion ProoO Level Controls - To Be Pressure Gauges To Be Condenser Cooling Water ... 

Figure 14-2B. Typical Holloshaft construction for vertical induction motor, weather-protected construction. (Used by permission Bui. BR 509-91B 1991, U.S. Electrical Motors, Div. Emerson Electric Co.)...

II. Weather protected Weather protected I Weather protected II... 

A weather-protected Type II machine shall have, in addition to the enclosure defined for a weather-protected Type I machine, its ventilating passages at both intake and discharge so arranged that high-velocity air and air-borne particles blown into the machine by... 

Motor enclosures for outdoor use are NEMA weather-protected Type II, totally enclosed, fan-cooled, or drip-proof with weather protection. Motors of the latter type are widely used. Not only are they less expensive than the other types, but they also have a service factor of 1,15. The above enclosure types are all suitable for the Class I, Group D, Division 2 classifications usually encountered. 

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