Message-ID: <598593FD.8070804@posteo.de>
Date: Sat, 05 Aug 2017 11:46:37 +0200
From: DK7FC <selberdenken@posteo.de>
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References: <0883B95D3F4D417F975C59A900E1A838@gnat> <272A11EB6A80467D9FA04EFAF51DD15A@ASUS>
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Subject: Re: LF: RE:G4HUP aerial current meter
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Status: RO

Hi Ian,

When the range of a current tranformer should be increased from 1A to 
10A, the best way is to increase the number of turns of the secondary 
winding by a factor 10. This transforms the current down by a factor 10 
(not up) in the secondary winding...
I*N has the same value on both sides (ideally/theoretically).

73, Stefan

Am 05.08.2017 11:35, schrieb i.frith@ntlworld.com:
> Hello Allan
>
> I assume the 10A mod is a matter of increasing the series R with the 
> meter to around 800k?
>
> I suppose a 3way switch and extra trim pot could be added to preserve 
> the 1A range too.
>
> Thanks for the note re-shipping Monday.
>
> Look forward to getting the Kit.
>
> 73
>
> Ian G4GIR
>
> -----Original Message----- From: Alan Melia
> Sent: Friday, August 4, 2017 9:36 PM
> To: rsgb_lf_group@yahoogroups.co.uk ; rsgb_lf_group@blacksheep.org
> Subject: LF: RE:G4HUP aerial current meter
>
> It has just occured to me that the 1A range may not be high enough for 
> some
> of the LF QRO merchants. There is a simple mod which will extend the 
> range
> up to 10A though you should be aware the ferrite core has not been 
> tested at
> this level of RF. These cores are used on mains leads carrying up to 
> 13A so
> I think they will be OK.
>
> Thank you to those showing interest, there are a few kits still 
> available.
>
> Alan
> G3NYK
>
>