[Amps] Big transformers?

[David G4FTC]

>From: Manfred Mornhinweg wrote

>The question now is very simple: For an 8kVA transformer,
>using common inexpensive standard 0.5mm thick silicon steel laminations
>(no Hypersil  nor anything like that), what's the optimal flux density?
>

Manfred,

A follow-up from my previous posting.

I’ve been doing a bit more research into transformer cores.

It would appear that HyperSil is no more than a standard grain-oriented 3% 
Si-Fe material which is available under a variety of different names such as 
Magnesil, Orthosil, Microsil, Supersil, etc., from a wide range of 
suppliers.

Grain-oriented 3% Si-Fe alloy was invented in about 1930 by Nicola Tesla who 
at the time was employed at Westinghouse. The alloy was patented and 
marketed by Westinghouse under the Trade Mark HyperSil.

Being a patented product, HyperSil became the defacto name for high 
performance transformer core materials. Although the patent has long since 
expired, the HyperSil is still used as a generic name for such cores. I 
haven’t been able to find if HyperSil is even still a valid Trade Mark.

Although Grain-oriented Si-Fe cores can operate with flux densities up to 
1.5 - 1.8 Tesla with reasonable core losses, there are more modern materials 
available such as the Co-V-Fe (Cobalt-Vanadium-Iron) alloys which can 
operate up to about 2 Tesla.  I have no figures about the relative costs but 
I would expect that the Co-V-Fe alloys would attract a premium.


Hope this helps

Regards

David

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