Author Topic: Can you guesstimate the VA capacity of a transformer?  (Read 1622 times)

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Can you guesstimate the VA capacity of a transformer?
« on: July 11, 2012, 03:59:11 pm »
Hi

If you have some random transformer that you pulled out of a piece of redundant equipment, can you hazard a guess as to a safe load, based on weight? Or would you just load it up and keep an eye on the temperature? What would be a safe temperature for a transformer anyway?

Cheers
John
 

Offline SeanB

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Re: Can you guesstimate the VA capacity of a transformer?
« Reply #1 on: July 11, 2012, 04:07:24 pm »
If it fits in the palm of your hand 5VA max. If you can fit it in your whole hand it is up to 100VA. If you need both hands to hold it up to 250VA. The size of the inner core determines the power it will handle. Compare to published figures for other transformers. Generally they should run at lower than 70c inside the core, measure with a thermocouple between the windings and the outer core. Not accurate, but a good place to start from.
 


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Re: Can you guesstimate the VA capacity of a transformer?
« Reply #3 on: July 12, 2012, 08:18:42 am »
On iron core, check this post -> https://www.eevblog.com/forum/projects-designs-and-technical-stuff/modding-an-isolation-transformer-please-advise/msg80157/#msg80157
3

Excellent, thanks - there was a link in that thread to an external website with some very useful info.

Cheers
John
 


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