They (at least the one with which I have some familiarity) close a semiconductor switch momentarily and monitor the rate of change of current as well as the steady-state current, i.e. if it looks as though the current is going to be above the maximum it will shut off.
Limiting current on a sub main
- Thread starter bernardgreen
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Ah. I had assumed they wouldn't do that since, particularly since it's presumably done repeatedly (and fairly frequently), that sort of treatment might not be good for certain types of load.
Kind Regards, John
I was talking about a business model which had an adverse effect on potential profits, so my statement obviously does not apply to the the NHS. As for metered water supplies, I agree that they encourage people to take steps which could result in their buying less of their product, but at least they do not have financial disincentives. With un-metered supplies, it obviously makes good business sense to do all they can to encourage/persuade customers to use as little as possible of their product (which is being provided for a fixed price!)!
Kind Regards, John
JohnW2 said:
How do you figure that?
3kVA = e 54.45
9kVA = e 117.20 (3 x 3kVA = e 163.35)
12kVA = e 180.11 (4 x 3kVA = e 218.20)
15kVA = e 206.57 (5 x 3kVA = e 272.25)
Although I'm sure that even if it were so, EDF probably has a "one supply per occupancy" rule.
It's interesting to note that it says that since 2010 this base tariff is no longer available for new services over 15kVA, so if you want more on a new service now you have to go with the Option Heures Creuse tariff (something akin to Economy 7) or Option Tempo (a complex scheme with blue, white and red periods on different days), with a minimum of 6kVA or 9kVA respectively.
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By getting my (mental) arithmetic wrong
.. I think the corner of my mind undertaking the mental arithmetic was thinking that the increases in subscription levels were 2-fold, rather than 3-fold!Assuming it's priced sensibly, that makes a lot more (business) sense. Even if there are generation/infrastructure problems at times of day of high demand, there must also be other times of day (and probably different days) when their generation capacity and infrastructure is very much under-used, so they ought to encourage as much use (hence purchase, hence profit) of their product as possible at such times.
Kind Regards, John
That would be zero, that would.
Pedantic semantics again, and I'm not even sure that you are necessarily right. "Load" is commonly used to mean "potential load" - as in statements such as "the kettle represents a load of 3kW (or 13A)". I'll leave you to study the dictionaries to see if you can "prove that you're right".
Kind Regards, John
While I do that, would you please do the following:
1) Explain why you are so dismissive, over and over again, of the notion that the meaning of words is important. I've asked you several times before, and you have always ignored me. It is outrageous, and unacceptable that you should keep on trying to make out that an argument is wrong, or a position invalid etc, on the basis that what words mean doesn't matter coupled with a refusal to justify that basis.
2) Explain how a "potential load" can be monitored by a device when it is not in the circuit.
1) Explain why you are so dismissive, over and over again, of the notion that the meaning of words is important. I've asked you several times before, and you have always ignored me. It is outrageous, and unacceptable that you should keep on trying to make out that an argument is wrong, or a position invalid etc, on the basis that what words mean doesn't matter coupled with a refusal to justify that basis.
2) Explain how a "potential load" can be monitored by a device when it is not in the circuit.
By using some method of measuring its impedance. It obviously has to be in some 'circuit' to do that, but not a circuit that does, or usually does, or can, 'power it'.
Kind Regards, John
So in the context of a load-limiting breaker which makes or breaks the circuit that powers the load, how does that monitor it?
I don't know how any such devices do it. Although, as I have said, it would not be without its potential problems, one way would be to apply power to the load through a 'substantial' (in relation to that of the expected load) resistance and measure the resultant (modest/small) current.
As I've said, I would personally not have thought that it would be very desirable to repeatedly apply 'full power' to the circuit (without a resistor/whatever), even for less than one cycle, not the least because there might be a fault in the load (or circuit) resulting in a very low impedance - although stillp seems to have indicated that such is one way in which it is done.
Kind Regards, John
That would do it!By getting my (mental) arithmetic wrong
The basic EDF plans don't seem to have changed from when I last studied them some years ago, although obviously the rates have altered somewhat! And it's good to see that nowadays they apparently offer single-phase supplies up to a reasonable level.
Comparing for a 9kVA supply, since that's the smallest now offered across all three plans, the base option is e117.20 per year plus 0.1467 per unit at all times. The Option Heures Creuse is little different in standing charge at e126.52 per year, and provides a cheap rate for 8 hours per day of 0.1114 but a higher standard rate of 0.16 per unit. Not really that much of a saving on the cheap rate compared to the difference in Britain on Economy 7 et al.
Option Tempo is the complex scheme with blue, white and red days, which EDF sets based on data from the French meteorological office. Each colored day is also divided into normal & cheap rates as with Option Heures Creuse, so there are six different rates! Standing charge is only slightly higher at e131.33. Currently blue: 0.0931/0.1111, white 0.13/0.1549, red 0.2366/0.6171 per unit, so best to avoid daytime use on red days! (I think they're restricted to a maximum of 22 or 23 days per year out of the 65 total days for red & white combined.) I know EDF used to (still does?) offer a unit which each evening received a signal to display an indication of which of the blue, white or red rates would apply on the following day.
So why did you get so bent out of shape over this?
I merely responded to your silly and unhelpful comment.
Kind Regards, John
You asked how the device could monitor how much current was flowing after it had opened the circuit so that no current was flowing.
I'm sorry you regard it as silly and unhelpful to point out that the load would be zero.
I'm sorry you regard it as silly and unhelpful to point out that the load would be zero.
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