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One voltage cycle of a three-phase system. A polyphase system (the term coined by Silvanus Thompson) is a means of distributing alternating-current (AC) electrical power that utilizes more than one AC phase, which refers to the phase offset value (in degrees) between AC in multiple conducting wires; phases may also refer to the corresponding terminals and conductors, as in color codes.
For example, R-22 has one carbon atom, one hydrogen atom (2−1 = 1), two fluorine atoms, and one chlorine atom (4−2−1 = 1), so it is chlorodifluoromethane, while R-134 has two carbon atoms (2−1 = 1), two hydrogen atoms (3−1 = 2), four fluorine atoms, and no chlorine atoms (6−2−4 = 0), so it is one of the tetrafluoroethanes. This ...
Tetrachloro-1,2-difluoroethane is a chlorofluorocarbon known as Freon 112, CFC-112 or R-112. It has a symmetrical structure CCl 2 FCCl 2 F and so can be called symmetrical tetrachlorodifluoroethane. "Symmetrical" may also be abbreviated to "s-" or "sym-". In contrast an asymmetrical isomer has formula CCl 3 CClF 2.
R-410A is a refrigerant fluid used in air conditioning and heat pump applications. It is a zeotropic but near-azeotropic mixture of difluoromethane (CH 2 F 2, called R-32) and pentafluoroethane (CHF 2 CF 3, called R-125). R-410A is sold under the trademarked names AZ-20, EcoFluor R410, Forane 410A, Genetron R410A, Puron, and Suva 410A.
Two-phase power can be derived from a three-phase source using two transformers in a Scott connection: One transformer primary is connected across two phases of the supply. The second transformer is connected to a center-tap of the first transformer, and is wound for 86.6% of the phase-to-phase voltage on the three-phase system.
2,2-Dichloro-1,1,1-trifluoroethane can be produced by reacting tetrachloroethylene with hydrogen fluoride in the gas phase. This is an exothermic reaction and requires a catalyst: This is an exothermic reaction and requires a catalyst:
A representative pressure–volume diagram for a refrigeration cycle. Vapour-compression refrigeration or vapor-compression refrigeration system (VCRS), [1] in which the refrigerant undergoes phase changes, is one of the many refrigeration cycles and is the most widely used method for air conditioning of buildings and automobiles.
R-407C is a mixture of hydrofluorocarbons used as a refrigerant. It is a zeotropic blend of difluoromethane (R-32), pentafluoroethane (R-125), and 1,1,1,2-tetrafluoroethane (R-134a). Difluoromethane serves to provide the heat capacity, pentafluoroethane decreases flammability, tetrafluoroethane reduces pressure. [ 1 ]