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Re: Transformer Ballasting
---------- Forwarded message ----------
Date: Fri, 17 Oct 1997 12:12:19 GMT
From: Mike Harrison <wwl-at-netcomuk.co.uk>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Transformer Ballasting
On Thu, 16 Oct 1997 15:18:22 -0600 (MDT), you wrote:
>
>
>---------- Forwarded message ----------
>Date: Thu, 16 Oct 1997 19:43:35 +0100
>From: Gwyn Zucca <gwyn-at-tcbod.demon.co.uk>
>To: tesla-at-pupman-dot-com
>Subject: Transformer Ballasting
>
>Hello All,
>
>I have tried searching the list archives for anything on the subject of
>current limiting power transformers, but I did not find exactly what I
>was looking for. The problem seems to be limiting the short out current
>without reducing the output voltage of the transformer. Obviously any
>resistance in circuit with the xfrm primary is going to develop a volt
>drop across it, and so the primary voltage will be lower than the rated
>output. The use of an inductive ballast, is going to have a similar
>effect. I have been experimenting with various arrangements, but have
>not yet achieved a satisfactory solution.
>
>Any thoughts, experiences on this subject would be welcome.
>
>See Ya...
>
How about high-wattage tungsten halogen lamp(s) in series with the
primary - these have very little resistance when cold, so little loss,
but increase rapidly when current exceeds a certain level to heat up
the filament. They also have the advantage of giving a visible
indication of over-current, and are very cheap!
'Trip' point could ba adjusted using different wattage lamps or
parallel combinations