On Aug 19, 3:03 am, mm wrote:
On Sun, 19 Aug 2007 02:54:32 +0100, John Rumm

wrote:
Fred wrote:

It's very much the issue! I recall stories as the poster had where the
starting of a fluorescent tube was equivalent to 1/2 hour running.

Analyse that statement logically and you will see it makes no sense...

First off, it's true, and it may be the basis for the original post,
so it's worth discussing.

Secondly, I would say that it does make sense**, but it's not accurate
and for someone who knows anything about the topic, it's not
believable.

Something that makes no sense, to me, would be something whose
intended meaning I can't discern.

**A lot of things use more electricity on start-up, so the sentence is
not illogical. But the numbers are wrong.


Well, Duh! His obvious point was that if you look at the real facts,
which he clearly presented, then it makes no sense, because the
current required in the few secs of startup would be huge. And I
think your definition of "makes no sense" equals "can't discern
intended meaning" isn't exactly mainstream. For example, if someone
said that Mars revolves aroung the Earth, the meaning is quite clear,
yet any reasonable person would say that makes no sense.





How much current would be drawn by say a single 56W tube? 230mA.

How long does it take to start? say 3 secs

So the current drawn in those three seconds would need to be 600 times
(i.e. 1800 secs over 3) the nominal current so as to consume the same
amount of energy, or 138A.

Any guesses as to how many tubes with that sort of inrush current you
could start on a circuit protected by a 6A breaker without tripping it? ;-)- Hide quoted text -

- Show quoted text -