[Boatanchors] Designing Isolation Xfmr; Need Advice

[hwhall at compuserve.com]

 >
There are idustrial control transformers with split windings (120/240 :
120/240) that can be wired as 120 V isolation transformers that often go
cheap by GE, Westinghoude, etc.
>

Something to consider, though, is that those split windings may have only
the enamel on the wires between pri & sec. I took one of those types apart 
once, on a toroid core, considering it for isolation use.  The two 
primaries were just laid over each other. Real isolation xfmrs have 
insulation between the primary & secondary, or even on separate bobbins.

Wayne
WB4OGM
 



-----Original Message-----
From: J. Forster <jfor at quikus.com>
To: Ken Woodside, WB8EQO <wb8eqo at yahoo.com>
Cc: boatanchors <boatanchors at mailman.qth.net>
Sent: Sun, Dec 16, 2012 1:35 pm
Subject: Re: [Boatanchors] Designing Isolation Xfmr; Need Advice

 
 
 
The 12V @ 5A will give you 60 Watts; the 24V @ 5A will give you 120 Watts. 
I'd look for an isolation transformer on eBay or surplus. 
 
There are idustrial control transformers with split windings (120/240 : 
120/240) that can be wired as 120 V isolation transformers that often go 
cheap by GE, Westinghoude, etc. 
 
FWIW, 
 
-John 
 
======= 
 
 
 
> Hi To All- 
> 
> I have several B.A.'s I want to check out... I would like to build an 
> Isolation Transformer for safety. I need some ideas & have a few 
> questions. 
> 
> I assume that there are two levels of such devices: 
> 1. Testing receivers or tranceivers in receive mode. (low amp draw)and 
> 2. Transmitters or transceivers transmitting (may be high amp draw) 
> 
> I wud like to build the former to start and to control costs. 
> 
> I understand I can use 2 back-to-back transformers that are equal, wired 
> secondary side to secondary side. 
> 
> Wud I be better with: two 12 volt 5 amp transformers or two 24 volt 5 amp 
> transformers (as an example)? 
> 
> Ideas on fusing?  Minimum Transformer size? Other guidelines? 
> 
> Many thanks to all. 
> 
> Happy Holidays! 
> 
> Ken AA8EE 
> former call sign WB8EQO 
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