VA to Milliamps conversion

[Clinton]

Hello,

Can someone assist me in converting 5Voltamps into Milliamps. The power supply is 24VAC.

THanks
Clinton

 

[k7elp60]

VA to watts

In simple terms VA=Watts. P=EI so 5/24=.2083 or 208.3Ma.
Usually in AC circuits that have reactance one has to take into consideration is the phase angle. So we would multiply the Ma times the cosine of the phase angle.

 

[Clinton]

Thanks,

Clinton

 

[jrtenn]

VA to watts

In simple terms VA=Watts. P=EI so 5/24=.2083 or 208.3Ma.
Usually in AC circuits that have reactance one has to take into consideration is the phase angle. So we would multiply the Ma times the cosine of the phase angle.

Greetings, retired engineer.

With the above formula, if we have an AC transformer that's rated 16.5 VAC at 40va, would the rough current available be:

40 / 16.5 = 2.4amps
or is it 40 / 16.5 = 240ma ??

That's the part that sometimes confuses me.

Thank you for a reply.

JRTENN

 

[kubeek]

Careful with that necromancy, this thread is over ten years old!
Anyway, my trusty calculator tells me that 40W/16.5V=2.42A. Why do you think it should be anything else than that?
If you want it in milliamps, then it becomes 2424 mA, definitely not 242mA.

 

[jrtenn]

Careful with that necromancy, this thread is over ten years old!
Anyway, my trusty calculator tells me that 40W/16.5V=2.42A. Why do you think it should be anything else than that?
If you want it in milliamps, then it becomes 2424 mA, definitely not 242mA.

Thank you! After perusing your kind answer, I finally located my trusty calculator-with-a-storage-memory, and entered the proper formula that you kindly verified into it. The cobwebs are lifted.

What made me question a bit more the actual ma rating, was that a 2.42 or so AC transformer / adapter -- at 16.5VAC and 40VA plate rating -- would be pretty hefty, yet the one in question is less than a pound, however is still rated 16.5V / 40VA. At times, just the transformers rated that high would seem to be an easy 2 lbs of "heft".

Regardless, the one I questioned is thus able to approach supplying as much as 2.42 amps or so, although common-sense says to not draw over perhaps 2amps, so as to provide a safety factor..

Thank you again, and the quagmire of my humble mind is now cleared.

JRTENN

 

[kubeek]

You could try actually weighing it, from what I found with a quick crawl on farnell one was around 700g, which is about 1.5lb for those who prefer obsolete units.

 

[jrtenn]

You could try actually weighing it, from what I found with a quick crawl on farnell one was around 700g, which is about 1.5lb for those who prefer obsolete units.

Thanks again.

OK, for the 16.5 VAC transformer label rated 40VA, the weight on accurate digital scale is 1,45 lbs / 658 grams, which appears right in the same expected ballpark as you previously mentioned.

So in actuality, that's not too "heavy" of a weight, especially when expecting ability to provide 2.0 to 2.42 amps..

Thank you again for the expertise and discussion.

Joe / Knoxville, TN
JRTENN

 

[Haighter]

Thanks again.

OK, for the 16.5 VAC transformer label rated 40VA, the weight on accurate digital scale is 1,45 lbs / 658 grams, which appears right in the same expected ballpark as you previously mentioned.

So in actuality, that's not too "heavy" of a weight, especially when expecting ability to provide 2.0 to 2.42 amps..

Thank you again for the expertise and discussion.

Joe / Knoxville, TN
JRTENN

I just want to thank you and Kubeek for a great laugh today. I haven't seen that much savagery in a threat in a long time. Also, thanks for the advice it helped me solve my problem today!