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In the United States, the efficiency of air conditioners is often rated by the seasonal energy efficiency ratio (SEER) which is defined by the Air Conditioning, Heating, and Refrigeration Institute, a trade association, in its 2008 standard AHRI 210/240, Performance Rating of Unitary Air-Conditioning and Air-Source Heat Pump Equipment. [1]
For example, if the imbalance is limited to 25% of the total load (half of one half) rather than the absolute worst-case 50%, then conductors 3/8 of the single-phase size will guarantee the same maximum voltage drop, totalling 9/8 of one single-phase conductor, 56% of the copper of the two single-phase conductors.
A new power quality standard, AS 61000.3.100, was released in 2011 [25] that details additional requirements. The new standard stipulates a nominal 230 V, and the allowable voltage to the customer's point of supply is, as mentioned, +10% to −6%. However, the preferred operating range is +6% to −2%. (244 V–225 V).
In 2006, McQuay was acquired by Daikin Industries, a global manufacturer of both commercial and residential air conditioning equipment based in Osaka, Japan. Daikin had annual sales of $13 billion in 2009. [2] Daikin was named one of the 100 most sustainable corporations for three years in a row by Corporate Knights, Inc., from 2007 through ...
A 50 Hz ±5 Hz vibrating-reed mains frequency meter for 220 V The world's first public electricity supply was a water wheel driven system constructed in the small English town of Godalming in 1881. It was an alternating current (AC) system using a Siemens alternator supplying power for both street lights and consumers at two voltages, 250 V for ...
A schematic representation of long distance electric power transmission. From left to right: G=generator, U=step-up transformer, V=voltage at beginning of transmission line, Pt=power entering transmission line, I=current in wires, R=total resistance in wires, Pw=power lost in transmission line, Pe=power reaching the end of the transmission line, D=step-down transformer, C=consumers.
For AC-operated devices (e.g. coaxial cable, loudspeakers), there may even be two power ratings, a maximum (peak) power rating and an average power rating. [ 5 ] [ 6 ] For such devices, the peak power rating usually specifies the low frequency or pulse energy, while the average power rating limits high-frequency operation. [ 5 ]
An electricity meter, electric meter, electrical meter, energy meter, or kilowatt-hour meter is a device that measures the amount of electric energy consumed by a residence, a business, or an electrically powered device over a time interval. Electric utilities use electric meters installed at customers' premises for billing and monitoring purposes.