[Coco] Step down transformer for use in UK / Use on TV in UK

[Gene Heskett]

On Thursday 15 February 2007, Leon Howell wrote:
>> In the UK, the standard voltage is 240 volts. Therefore, I need to
>> purchase a step-down transformer.
>
>If you use a step down transformer, be careful about the ac frequency.
> 50hz power supplies used at 60hz have been known to overheat.

Its the reverse of that Leon.  Using a 60 hz tranny on 50 hz, you need to 
derate it about 20% because of the lower frequencies increased heat due 
to core saturation effects.  And some real borderline, not enough iron in 
them cheapies are just asking for an unexpected visit from the fire dept.

Running a 50 hz rated transformer on 60 hz usually results in much cooler 
operation overall.  The core never comes anywhere near saturation then so 
its nice & efficient.

> I would 
> also suggest an external 12v power supply, or get a little switching
> power supply, like the kind used in modern external drives, etc.



-- 
Cheers, Gene
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Copyright 2007 by Maurice Eugene Heskett, all rights reserved.