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Power is determined from an AC voltage measured in volts RMS and an AC amperage measured in amps RMS, but there is really no such thing as "RMS power". People are using the term "RMS power", but that is not correct. it is actually "average power".
Why there is no such thing as 'RMS watts' or 'watts RMS' and never has been:
Wiki User
∙ 9y ago
Wiki User
∙ 15y agoIn DC, you don't need to worry about RMS values. The properties (I, V) do not change with time.
However, in AC, I and V are varying with time. If I have a pure sinusoidal voltage wave (DC voltage offset = 0) across a resistor, the average voltage = 0, but the resistor still gets hot, because power is still consumed. In order to evaluate AC power, we use root-mean-square (RMS) values for I and V. For discrete values, RMS = sqrt{(x1^2 + x2^2 + ... + xn^2) / n}. You use integration for continuous functions, such as a sine wave. Power = I_rms * V_rms. This exercise seems trivial for a resistor, because when I > 0, so is V. Power > 0 in the case of a resistor. Things get more complicated when capacitors and inductors are involved, where I and V don't always have the same signs. Using RMS values will give a more realistic view of power consumption for these elements.
Wiki User
∙ 11y agoFor sinusoidal voltages and currents, the root-mean-square (r.m.s.) value is 0.707 times the amplitude (peak value).
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What is the rms current for an 8.0 µF capacitor attached to a 120 V rms 60 Hz source?
The RMS current for an 8.0 µF capacitor attached to a 120 V rms 60 Hz source is 39,798 amperes.
How do you determine form factor of sine wave?
Form factor of any periodic wave is [RMS CURRENT]/[AVERAGE CURRENT]. For sinusoidal wave RMS current=I/sqrt(2); AVERAGE current=2I/pi; Therefore, Form factor=[I/sqrt(2)]/[2I/pi] =pi/{2*sqrt(2)} =1.11
What is the relation between peak current and effective current of an AC power system generated by commercial power companies in the US?
The effective current is the square-root of the average value of the current-squared, root-mean-square or rms for short. That is because the power in a resistive load like a water heater is proportional to the square of the current. The rms voltage of an ac supply gives the same heating effect as a dc supply of the same voltage. The peak current is sqrt(2) times higher. The rms voltage and current are always quoted when referring to an ac power supply.
Can you please explain what RMS value is?
RMS stands for Root Mean Square. It is a method of averaging where you take the squares of a bunch of samples, average them with an ordinary mean, and then take the square root. This gives greater weight to larger values. In the case of an ordinary sine wave, the RMS value is 0.707 times the peak value, 0.707 being 1/2 the square root of 2, and the peak value being one half the peak-to-peak value. For example, in the US, a "standard" 117VAC line voltage is actually an RMS voltage that corresponds to a peak voltage of 166VAC.RMS is a necessary unit because, often, the waveform is not sinusoidal, it is sawtooth, such as in a power supply. Using an ordinary VOM, calibrated for a sinusoidal AC scale in such a case, will give an inaccurate reading of ripple voltage. Most modern DMM's have a true-RMS mode which will work correctly by using sampling and analysis technology.RMS is also a necessary unit because RMS is a better indication of how much power a signal can impart to a load.Another answerRMS stands for Root Mean Square value.In electrical technology, where alternating current (AC) is used, RMS Voltage and RMS Current (Amps) must be used to calculate the average power supplied or consumed. See the link below on how to find the RMS.In fluid flow technology related to gases, velocity is calculated as an RMS value because it can be used to find the average velocity of an ideal gas.Yet Another AnswerBecause a AC current is continuously varying in both magnitude and direction, it's necessary to measure it in a meaningful way. The rms-value of an AC current is equivalent to the value of DC current necessary to do exactly the same amount of work. For example, a sinusoidal AC current which peaks at 100 A has an rms-value of 70.7 A, and does exactly the same amount of work as a DC current of 70.7 A.
What is rms unit?
The abbreviation, 'r.m.s.', represents 'root mean square', which is a way in which a.c. current (and voltage) is measured so that it may be compared with a d.c. current that does the same amount of work.
Why you are calculating average and rms values for ac supply?
We will always calculate rms value only since the average value of ac current or voltage is zero. So we are using rms values in the ac circuit to calculate the power and to solve an ac circuit.
The average value of a single sine wave of AC is 42.5amps. what is rms value?
Average Current = 0.636 * (Peak Current)so Peak Current = (Average Current)/0.636RMSCurrent = 0.707 * (Peak Current)so Peak Current = (RMS Current)/0.707Because both equations are in terms of Peak Current, we can set them equal to each other.(Average Current)/0.636 = (RMS Current)/0.707(42.5)/0.636 = (RMS Current)/0.707thenRMS Current = (0.707)(42.5)/0.636 = 47.24 ampsAnother AnswerSince the average value of a single sine wave is zero, you cannot calculate its r.m.s. value!
What is the relationship between peak current peak to peak current and RMS current?
RMS is the root mean square value.(in alternating current only)
What is 10000 rms?
rms stands for root mean squared. rms voltage is a way of measuring a sort of average alterating current voltage as distinguished from peak-to-peak voltage. Likewise for ac rms current.
What is the rms current for an 8.0 µF capacitor attached to a 120 V rms 60 Hz source?
The RMS current for an 8.0 µF capacitor attached to a 120 V rms 60 Hz source is 39,798 amperes.
How electronic energy meter works?
By Using CT and PT, The RMS Current, RMS Voltage, True Power are measured by using Sample and Hold Circuits and converts into ADC then using Microcontroller or Microprocessor to calculate the Real values.
How do you get kilowatts if given voltage?
If voltage is given as RMS voltage (which it normally is), simply multiply the number of volts by the RMS current (as number of amps), and then divide by one thousand. Power (in kW)=Voltage (RMS volts) * Current (RMS amps) / 1000 (watts/kW)
Find rms and average value of 15a current?
RMS is just 15/sqr2 average is 15 * 0.637
How do you convert an RMS current value to a DC value?
RMS current is converted to DC current by using a rectifier. Capacitors and other components are used to make a cleaner DC output with less ripple.
How to calculate the average power in labview?
If you are talking electrical power, take a sample as an array of double of the current, same for voltage, use the RMS block on both I, V and multiply the result.
Conversion of RMS CURRENT to peak current?
In an AC circuit the voltage and current are n the form of a sine wave that goes between a maximum and minimum value 60 times a second. Measuring the difference between these values is a peak-to-peak measurement. Root Mean Square (RMS) computes an average (mean). To convert RMS to peak, multiply the RMS figure by 1.41. 1.41 is an approximation of the value of the square root of 2.
What is difference between RMS and true RMS?
RMS means root mean square and watts means power. What a difference! Scroll down to related links and look for a neat pressure converter at"Root Mean Square" und knowlege about "Watt" Watts root mean square is the effective value of alternating current electrical power compared to direct current power. Scroll down to related links and look for "Why there is no such thing as 'RMS watts' or 'watts RMS' and never has been". RMS watts is meaningless, but we use that term as "an extreme shorthand" for power in watts calculated from measuring the RMS voltage.
