Electrical equipment testing

Inhibited grades of 1,1,1-trichloroethane are used in hundreds of different industrial cleaning appHcations. 1,1,1-Trichloroethane is preferred over trichloroethylene or tetrachloroethylene because of its lower toxicity. Additional advantages of 1,1,1-trichloroethane include optimum solvency, good evaporation rate, and no fire or flash point as determined by standard test methods. Common uses include cleaning of electrical equipment, motors, electronic components and instmments, missile hardware, paint masks, photographic film, printed ckcuit boards, and various metal and certain plastic components during manufacture (see Metal surface treatments). 

Current density can be increased without impairing the quaUty of the copper by polishing the cathode surface by brief periodic current reversals (PCR). Reversed current electrolysis, first developed for electroplating, was tested in 1952 for copper refining. Although good results were obtained, no suitable electrical equipment for current reversal was available. The thyristor-controUed siUcon rectifier, introduced in the 1960s, provided a means for... 

Enclosure for electrical equipment up to lOOOV. Test criteria and design tests Industrial controls and systems. Enclosures... 

Intrinsic Safety. Static electrical concepts such as minimum ignition energy do not directly apply when assessing the safety of electrical circuits such as radios, flashlights and instmmentation. Intrinsically safe electrical equipment is usually available which has been subjected to fault analysis and testing. The equipment must be certified for the flammable atmosphere in which it will be used (NFPA 497). Refer to texts on Intrinsic Safety such as [63]. 

All electrical equipment shall be constructed, wired, and tested in accordance with the NFPA 70 National Electrical Code and Specificaton ME-O-JFI 15. 

All wiring and electrical equipment in chemical plants should be installed in accordance with the National Electrical Code. Electrical equipment for use in hazardous locations should be recognized by Underwriters Laboratories (or other testing organizations recognized by the authority having jurisdiction) for the conditions to be encountered. 

Turn off power to electrical equipment before tests and repairs tlien lock and tag it out so it does not turn on by accident. Follow your company s lockout/tagout procedures. 

The efficiency of transformer oils as dielectrics is measured by electric strength tests. These give an indication of the voltage at which, under the test conditions, the oil will break down. Various national standards exist that all measure the same basic property of the oil. There is an international specification, lEC 296/1982, which may be quoted by equipment manufacturers in their oil recommendations. 

Some specific internationally recognized electrical hazardous location equipment testing agencies are listed in Table 16 below. 

ASME ASSE ASTM AWWA BACT BASEEFA Engineers American Society of Mechanical Engineers American Society of Safety Engineers American Society for Testing and Materials American Water Works Association Best Available Control Technology British Approval Science for Electrical Equipment in Flammable Atmospheres... 

Once a hazardous location has been classified, appropriate electrical equipment must be chosen for that area. In general, equipment must be approved for use in that hazardous classified area. Testing labs such as UL test, label, list, or approve equipment suitable for installation in accordance with their legislated code. 

The gravitational field affects olfaction as it does vision, audition, or vestibular function. It could impair detection of dangerous fumes or burning electrical equipment in airplanes or space vehicles. Astronauts also report altered perception of food flavors under weightless conditions. Men and women tested with four scratch-and-sniff odor samples of the University of Pennsylvania Smell Identification Test identified odors more poorly when in an upside-down position (Mester eta/., 1988). 

The ISO/IEC 17025 standard (ISO/IEC 2005) has the title General requirements for the competence of testing and calibration laboratories and is the main standard to which analytical chemical laboratories are accredited. The word calibration in the title arises from the use of the standard to accredit bodies that calibrate instruments such as balances, electrical equipment, and utility meters. It must also be stressed that the standard is not written for analytical chemists, but for any measurement scientists. Therefore, the terminology tends to be general, and the emphasis is sometimes not clear for the chemist. However, the standard is wide ranging and covers a whole community of measurement scientists. 

For the control/monitoring instrumentation, regulating devices, and any associated electrical equipment, predelivery testing and calibration is normally the responsibility of the instrument/equipment manufacturer and should be carried out to approved written procedures using calibration test equipment that is traceable back to agreed-upon national standards. The test equipment must have precision, accuracy, and repeatability that are higher than that of the instrument being calibrated. 

E-mail Address info vertmarkets.com Web Address www.electricnet.com ElectricNet is a gateway to valuable industry information pertinent to those who design, manufacture, construct, startup, test, repair, service, calibrate, maintain or sell electrical equipment, power apparatus, plant electrical facilities or generation, transmission or distribution equipment or systems. 

Environmental Enclosures Enclosures for valve accessories are sometimes required to provide protection from specific environmental conditions. The National Electrical Manufacturers Association (NEMA) provides descriptions and test methods for equipment used in specific environmental conditions in NEMA 250. IEC 60529, Degrees of Protection Provided by Enclosures (IP Code), describes the European system for classifying the degrees of protection provided by the enclosures of electrical equipment. Rain, windblown dust, hose-directed water, and external ice formation are examples of environmental conditions that are covered by these enclosure standards. 

A number of modern full-scale fire test methods have been developed for products, relying on heat release rate measurements, such as those involving testing of upholstered furniture (ASTM E 153792 and CA TB 13391), mattresses (ASTM E 1590,85 CA TB 129,82 CA TB 603,88 16 CFR 1633,19 and ASTM F 1085 [Annexes A1 and A3]171), stacking chairs (ASTM E 1822172), electrical cables (ASTM D 5424,173 ASTM D 5537,174 and UL 1685123), plastic display stands (UL 1975),175 other decorative items (NFPA 289,176 a generic furniture calorimeter test), electrical equipment (UL 2043),120 or wall-lining products (NFPA 265,116 NFPA 286,115 ASTM E 2257,177 and ISO 9705178). In fact, room-corner tests are now being used in the codes, as alternatives to replace the... 

---