230V/240V Question

[stillp]

we haven't got a clue as to what what voltage variation is permissible at frequencies which are not 'at nominal' (i.e. 'at', or, at least, very close to, 50 Hz), but which are still within the acceptable frequency range.

What would you do if you did have a clue?

 

[JohnW2]

I really don't see what analogy you're trying to draw here.

Stating that, for example, "The boiling temperature of water is 100° C" does not have a precise meaning unless the pressure is specified

... which is absolutely true.

... just as "The supply voltage shall be X ±10%" does not have a precise meaning unless the frequency is specified.

... which makes absolutely no sense to me. In what way do limits of "230V ±10%" not fully define what range of voltages is permissible, regardless of anything else??

Kind Regards, John

 

[JohnW2]

we haven't got a clue as to what what voltage variation is permissible at frequencies which are not 'at nominal' (i.e. 'at', or, at least, very close to, 50 Hz), but which are still within the acceptable frequency range.

What would you do if you did have a clue?

It's nothing to do with me - it's the suppliers who have to ensure that their supply remains within permitted limits of both voltage and frequency.

My understanding is that, in practice, they are very good at keeping the frequency very close to 50 Hz, which means a lot of this is probably rather moot - but it makes the reason for the wording of the ESQCR regulation even more difficult to understand.

Kind Regards, John

 

[stillp]

In what way do limits of "230V ±10%" not fully define what range of voltages is permissible, regardless of anything else??

Because it's not just an abstract parameter, the voltage and frequency are 2 interrelated parameters of the supply of energy.

 

[PBC_1966]

Stating that, for example, "The boiling temperature of water is 100° C" does not have a precise meaning unless the pressure is specified, just as "The supply voltage shall be X ±10%" does not have a precise meaning unless the frequency is specified.

But the temperature at which water boils is dependent upon pressure. The voltage of an AC sinewave is not dependent upon its frequency.

 

[stillp]

But the voltage and frequency of a supply are closely interrelated.

 

[JohnW2]

In what way do limits of "230V ±10%" not fully define what range of voltages is permissible, regardless of anything else??

Because it's not just an abstract parameter, the voltage and frequency are 2 interrelated parameters of the supply of energy.

Given the tight limits on frequency, I doubt that is really an issue but, if it were, and as I keep saying, IF they have some reason for wanting frequency-dependent voltage limits, it behoves them to actually specify them - it seems crazy to leave the suppliers (as well as us) having to guess! (and, quite frankly, I haven't a clue what I would guess).

This whole protracted exchange seems to have arisen because of your desire to defend what appears to be unsatisfactory wording of the ESQCR regulation which you kindly quoted for us. I strongly suspect that the truth is that they are happy to stick with the -15%/+10% voltage limits for any frequency within the permitted range (50 Hz ±1%), the only problem being the way they chose to word the regulation.

Kind Regards, John

 

[stillp]

(and, quite frankly, I haven't a clue what I would guess).

It's lucky you're not a network engineer then John!

 

[stillp]

This whole protracted exchange seems to have arisen because of your desire to defend what appears to be unsatisfactory wording of the ESQCR regulation which you kindly quoted for us. I strongly suspect that the truth is that they are happy to stick with the -15%/+10% voltage limits for any frequency within the permitted range (50 Hz ±1%), the only problem being the way they chose to word the regulation.

Not defending John, just trying to help you understand.
Where did you get -15% +10% from?

 

[JohnW2]

Not defending John, just trying to help you understand.

One does really need any technical knowledge (electrical, statistical or anything else) to see that the wording of the regulation is unsatisfactory. If a regulation specifies voltage limits for one specified frequency, it is apparent that it leaves readers without any idea what the limits would be at other frequencies.

Where did you get -15% +10% from?

Were they not the voltage limits (for 'at nominal frequency') in the ESQCR regulation you posted? (I can't really be bothered to hunt through 15 pages to find out!)

Kind Regards, John

 

[stillp]

Not defending John, just trying to help you understand.

One does really need any technical knowledge (electrical, statistical or anything else) to see that the wording of the regulation is unsatisfactory. If a regulation specifies voltage limits for one specified frequency, it is apparent that it leaves readers without any idea what the limits would be at other frequencies.

Where did you get -15% +10% from?

Were they not the voltage limits (for 'at nominal frequency') in the ESQCR regulation you posted? (I can't really be bothered to hunt through 15 pages to find out!)

Kind Regards, John

I would rather say that the regulation gives adequate information for those who have to comply with it and enforce it. No, those are not the ESQCR limits. Please try to pay attention!

 

[JohnW2]

(and, quite frankly, I haven't a clue what I would guess).

It's lucky you're not a network engineer then John!

Well, if I were, I suppose I'd guess what I'd recently written - that the only problem is poor wording and that the intent was that the stated voltage limits applied to a supply of frequency anywhere within the permitted frequency range.

... but if I were a network engineer, it really would be far from satisfactory if I were having to guess about the meaning of a fundamental regulation to which my industry was meant to be working!

Kind Regards, John

 

[PBC_1966]

Were they not the voltage limits (for 'at nominal frequency') in the ESQCR regulation you posted?

-6% / +10%

 

[JohnW2]

I would rather say that the regulation gives adequate information for those who have to comply with it and enforce it.

Maybe guessing about meanings of regulations is part of their job description

No, those are not the ESQCR limits. Please try to pay attention!

Ah yes, I should have said -6%/+10% ('co-incidentally' the same as the transitional harmonised figures for the UK!) - the figures I wrote were the ones you mentioned for industrial equipment.

Kind Regards, John

 

[ban-all-sheds]

...but the pressure varies even at sea-level.

Standard pressure doesn't.

But FGS don't tell Winston that.