RMS voltage

Universal Motors. A universal motor is a series-wound motor designed to operate at approximately the same speed and output on either direct current or single-phase alternating current of a frequency not greater than 60 cycles/s and approximately the same rms voltage. There are two types ... 

This instrument was developed from the hot-wire ammeter, some examples of which can still be found. In the modem equivalent, the current to be measured (or a known proportion of it) flows through a small element that heats a thermocouple, so producing a rms voltage at its terminals, which is a function of the current. This voltage then supplies a current to a permanent magnet, moving-coil movement. 

FIGURE 2. Peak EEG root-mean-square (RMS) voltage from 0-20 hertz (Hz) as a function of dose for phencyclinoids... 

Then to account for the fact that the actual dissipation depends on ESR, which increases substantially at low temperatures, a derating on the allowed RMS voltage is introduced. So at +5°C, we need to derate the RMS voltage by -7%, at -15°C by -15%, at -35°C by -20%, and at -55°C by -30%. But you may need to talk to your vendor to get information specific to his or her part. Everybody has differing guidelines since the technologies are quite diverse. 

Drop Out. Voltage drop out includes both severe RMS voltage sags and complete interruption of the applied voltage followed by immediate reapplication of the nominal voltage. The interruption may last up to 20 msec. The transient typically results from the occurrence and subsequent clearing of the faults in the distribution system. 

This low-frequency noise must be considered superimposed to the thermal noise whose rms voltage is given by vms = (4kTR A/)I/2. A straightforward expression for the thermal noise is the following = 4 X 10 9... 

This equation is the basis of both the electrovibration sind vibration potential listed in the electrokinetic phenomena of Table 9.10. In these cases, the root mean square (rms) voltage i=E L) is either measured as in the case of the colloid vibration potential or induced by an electrode and the rms pressure fluctuations (= AP) at the same fi quency are either induced by an ultrasonic actuator or measured with a pressure transducer, as in the case of electrovibration. 

EC60038 gives the standard voltages for electrical equipment. However, for cables the AC rms voltages are defined for example in 1EC60502, in terms of their line-to-earth and line-to-line values. 

To find a root-mean-square (rms) value of a function of time, the function is first squared, then the mean value is taken, and then the root of the mean. The rms value must be used when power and heat effects are of interest (W = Vrms/R). From Eq. (3.42), it is clear that the rms value of a sine wave is l/s/2 of the peak value. Dealing with other waveforms, the relationships among peak, mean, and rms values will depend on the waveform. Many AC voltmeters display rms voltage, but actually measure the mean value. Such practice introduces errors for non-sine waveforms. 

When dealing with power spectra related to, for example, rms voltage v s according to W = Vms/R> F(tJ) represents the distributed power spectrum the density of signal power ptr frequency bandwidth. The unit for F(w) (e.g., when dealing with noise spectra) may be pVrms/VHz. When the spectrum is plotted with amplitude per VHz on the y-axis and frequency on the x-axis and scaled so that the area under the F((o) curve is equal to the total rms value in the time domain (Plancheral s theorem), the spectrum is called a power density spectrum. A less stringent definition is simply that a spectrum is called a power spectrum when the function is squared before analysis. 

AC Electro-Osmotic Flow, Fig. 5 Experimental data for ACEO pumping of KCl around a microfluidic loop, one-fifth covered by the asymmetric planar electrode array of Fig. 4a. (a) Contour plot of mean velocity versus AC frequency and RMS voltage at a bulk salt concentration of 0.1 mM (Reproduced from [3]), where electrode... 

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