just did not wanted to start a rather offtopic discussion about it.
so went the simple route.
rather, i should have made a post like..
"PS for those who don't know: watts = volts x amps = VA"
thank You helpfull member, but that information is incorrect, unless the traffo has a power factor of 1. in real life they do not. safer to assume 0.9 powerfactor and go for a traffo therefore 10% more in VA than the watts required.
but why would i had done that?
if someone would be interested, would ask about it.
then it would be correct to take things offtoppic.
i wanted to avoid this.
meanwhile , the statement of VA=W is incorrect, and may -or may not- mislead.
wanted to avoid that too, in a minimalistic, simple way.
i consider it job done.
and YESS i'm helpfull, when there is a demand for it.
so went the simple route.
rather, i should have made a post like..
"PS for those who don't know: watts = volts x amps = VA"
thank You helpfull member, but that information is incorrect, unless the traffo has a power factor of 1. in real life they do not. safer to assume 0.9 powerfactor and go for a traffo therefore 10% more in VA than the watts required.
but why would i had done that?
if someone would be interested, would ask about it.
then it would be correct to take things offtoppic.
i wanted to avoid this.
meanwhile , the statement of VA=W is incorrect, and may -or may not- mislead.
wanted to avoid that too, in a minimalistic, simple way.
i consider it job done.
and YESS i'm helpfull, when there is a demand for it.
Actually the context is well established, it's DIY audio.
In which context it will be found that:
watts = volts x amps = VA
I think it's worth noticing that nobody has posted any numbers showing this to be wrong. What's the matter with you make-it-complicated guys, come on and show some follow through.
.
Touche'. I'm not disagreeing. I would hate to have to find an instance here at diyA where the textbook difference was vitally important.
whenever You want X watts from a traffo, at least consdier the datasheet if it has and see the powerfactor it has.. some might be as low as 0.8.
in that case the 100 VA rated traffo would be 80 watt.
and 100 != 80 in my book.
if no info is found then usually 0.9 powerfactor is a more-or-less realistic guess.
but assuming powerfactor of 1 is never a good idea.
never ever.
in that case the 100 VA rated traffo would be 80 watt.
and 100 != 80 in my book.
if no info is found then usually 0.9 powerfactor is a more-or-less realistic guess.
but assuming powerfactor of 1 is never a good idea.
never ever.
.
No, assuming a power factor (it's two words) of one is an excellent idea, since that's the case.
Or...no...now I have to eat my words, because actually power transformers are only 95%-plus efficient. So actually I'm only 95% correct.
Then again...if I'm 95% correct, 5% wrong...then you're 5% correct, 95% wrong...I wonder what it all can mean?
Oh wait, I know! It means that:
watts = volts x amps = VA
For those who might not know, "traffo" is what experts say when they mean "power transformer." As you might expect, they're very busy and have no time to waste, least of all on correct terminology that might not confuse newcomers.
By the way, power transformers (correctly: traffos) are quite commonly 99% efficient. But that doesn't really change anything, different ratio, same principle.
.
No, assuming a power factor (it's two words) of one is an excellent idea, since that's the case.
Or...no...now I have to eat my words, because actually power transformers are only 95%-plus efficient. So actually I'm only 95% correct.
Then again...if I'm 95% correct, 5% wrong...then you're 5% correct, 95% wrong...I wonder what it all can mean?
Oh wait, I know! It means that:
watts = volts x amps = VA
For those who might not know, "traffo" is what experts say when they mean "power transformer." As you might expect, they're very busy and have no time to waste, least of all on correct terminology that might not confuse newcomers.
By the way, power transformers (correctly: traffos) are quite commonly 99% efficient. But that doesn't really change anything, different ratio, same principle.
.
Last edited:
effeciency will have variation depending on load, and a set of other factors.
and watts are still not = VA.
this has been pointed out for You in other threads too.
quit trolling, simply accept the fact that VA != Watts.
rather , you can still say You prefer personally to treat them as equal.
none would ever argue that.
but stating VA=watzts as a fact, is nothing but pure ********.
and there is no way to defend it.
and watts are still not = VA.
this has been pointed out for You in other threads too.
quit trolling, simply accept the fact that VA != Watts.
rather , you can still say You prefer personally to treat them as equal.
none would ever argue that.
but stating VA=watzts as a fact, is nothing but pure ********.
and there is no way to defend it.
.
Descending to profanity and 8th grade name calling does not make you look good.
Meanwhile, no, nothing has been "pointed out" to me, although certainly others have made invalid claims similar to yours. You join them in the 95% wrong group.
But after all this, what's left to say? I can only assure poor, struggling newbies, trying to get a grip on this stuff, that they'll be perfectly safe when they apply the formula:
watts = volts x amps = VA
However, as of now I'll refer to this as a rule of thumb. That might bring some peace around here, which would be a nice change. Only adding one word to implore that the KISS rule be observed, because newbies usually don't own scientific calculators.
Having said which, the last word is yours.
.
Descending to profanity and 8th grade name calling does not make you look good.
Meanwhile, no, nothing has been "pointed out" to me, although certainly others have made invalid claims similar to yours. You join them in the 95% wrong group.
But after all this, what's left to say? I can only assure poor, struggling newbies, trying to get a grip on this stuff, that they'll be perfectly safe when they apply the formula:
watts = volts x amps = VA
However, as of now I'll refer to this as a rule of thumb. That might bring some peace around here, which would be a nice change. Only adding one word to implore that the KISS rule be observed, because newbies usually don't own scientific calculators.
Having said which, the last word is yours.
.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.