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本帖最后由 stey 于 2013-5-18 15:05 编辑 $ i& t& u4 u, @* K
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这两个名称常常搞混淆,我比较同意以下这个说法(摘自yahoo)8 G! D4 N8 u9 j1 j
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Rated and nominal AC voltage?, Z' S- }6 w! `
, r% P# W- a; \ }7 G1.What is Rated AC voltage? Why we would like to state Rated instead of Nominal?+ @7 i) r8 b9 \6 G& o9 i- c
2.What is Nominal AC voltage?
4 K( ]1 t, u6 W" j/ @9 t3.Explain rms value for AC voltage. What is it's relation to Rated/Nominal Voltage?
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5 Q# M7 ], p& p; ?( NBest Answer - Chosen by Asker; m6 J% E5 i, l- m9 [4 I
Rated AC voltage might be the nominal voltage at which a piece of electrical equipment is designed to operate. In the case of a light, heater or motor, the operation at the rated voltage would provide the rated performance. Most equipment can operate at 5 or 10% above or below the rated voltage without much change in performance.9 N5 o9 h8 f# u3 j3 Y4 j
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Rated voltage could also be the maximum voltage that a type of wire, plug, socket or circuit breaker is designed for. In that case, the rated voltage may be considerably higher than the nominal voltage.
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' \; F. X B" f9 c2 X& BNominal voltage is the standard value that is used when referring to a voltage level. If the nominal voltage is 220 volts, the actual voltage might be 5 or 10% higher or lower.5 g! J) }4 }* x9 m8 i- X" M6 L
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The RMS value of an AC voltage is the effective value. It is the value that is usually stated when refering to an AC voltage. RMS stands for root mean square. RMS is calculated by calculating the square root of the average of the instantanious voltages making up one cycle of the waveform. It can be calculated or measured for any waveform including square waveforms and distorted sine waveforms. For an undistorted sine wave, the RMS voltage is the peak voltage divided by the square root of 2.$ i# w: v: r* v, _
4 N4 a; g) u$ w/ d6 s, QNominal and rated AC voltages are usually RMS values.: M. m1 H* i- s" r1 Q: g- u3 R; W
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