[Tagging] Feature Proposal - RFC - Power pole extension
61sundowner at gmail.com
Thu Feb 16 05:01:43 UTC 2017
On 16-Feb-17 01:00 PM, John F. Eldredge wrote:
> The RMS voltage of an alternating-current electrical source is the
> direct-current voltage that would supply the same power into a
> resistive load. That is to say, imagine you have an AC power source
> operating a heating element, and a DC power source operating an
> identical heating element. The DC connection powers the heating
> element continuously. The AC signal starts at zero volts, increases to
> a peak, then decreases back to zero. Then it does that again, to a
> negative voltage (the electrons flow in the opposite direction). The
> heating element doesn't care which direction the electrons are
> flowing; both directions produce the same amount of heat. If the net
> heat production from the AC-powered heating element is the same as the
> net heat production from the DC-powered element, then the Root Mean
> Square voltage of the AC power source is the same as the constant DC
> voltage from the DC power source.
Off topic warning.
Johns definition above is correct ..
These are fundamental to any electrical person.
The AC voltage can be stated in various ways .. where the statement of
voltage does not include rms, peak or peak to peak most people would
take the statement as being rms.
From a simple maths viewpoint:
The relationship of RMS (route mean squared), peak and peak to peak are
very well defined mathematically for a pure sine wave;
peak to peak = peak x 2
RMS = peak x 0.707 (or the reciprocal of the square route of two, if you
need more digits)
Thus 220 v RMS will be 311 v peak and 622 v peak to peak.
220 v RMS single phase voltage system resolves into a 3 phase system of
381 v RMS, as the 220 v is from one line to neutral, where as the 3
phase voltage is from one line to the other.
Again there is a simple mathematical vector relationship between the
single phase and the 3 phase voltages.
> On Feb 15, 2017 4:42 PM, "Warin" <61sundowner at gmail.com
> <mailto:61sundowner at gmail.com>> wrote:
> On 15-Feb-17 05:52 PM, Jherome Miguel wrote:
>> On Feb 13, 2017 4:19 PM, "François Lacombe"
>> <fl.infosreseaux at gmail.com <mailto:fl.infosreseaux at gmail.com>> wrote:
>> Hi Warin,
>> 2017-02-13 8:42 GMT+01:00 Warin <61sundowner at gmail.com
>> <mailto:61sundowner at gmail.com>>:
>> In Australia;
>> Heavy industry gets 3 phases.
>> Same in Europe, 2-phases or 3-phases depends on needs.
>> Here 3-phases for heavy industry :
>> 2-phases for train traction (2 separate circuits of 2 phases
>> each) :
>> From public power grid :
>> To traction substation :
>> For the Philippines, two or three phases for the primary are for
>> large commercial customers, but the output, it is three-phase
>> (220/380, 220/380/440, 440/760, 660/1150, 880/1530, and others,
>> all 60 Hz). Households use single-phase, either two-wire (220
>> volts) or three-wire systems (220/440 volts, though electricity
>> meters show "240 volts", which is within the tolerance of 220
>> volts, the peak voltage of one phase wire of the system
> Errr most places this is the RMS voltage, not the peak voltage.
> The 240 220 230 volts conflicts have been discussed for many years
> at an international level. Now they agree that their present
> tolerances encompass an agreed range ... that encompasses all
> those voltages.
> Possibly you think the peak voltage is the line-line voltage, right,
> while RMS voltage is line-neutral voltage. Is that correct?
No. See the above.
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