[R-390] Re: R-390 digest, Vol 1 #496 - 8 msgs

Mon, 16 Dec 2002 13:20:39 -0500

Hello,

The 187 ohm vs 150 ohm disrepancy that you report could be due to 
measurement errors.  Yes, the higher voltages must be used with discretion.  
  I like to see meter readings in the multiple volt region where my 
instruments give better accuracy.

Drew

>Date: Fri, 13 Dec 2002 18:08:39 -0800
>From: Dan Merz <[email protected]>
>Reply-To: [email protected]
>To: Dave and Sharon Maples <[email protected]>,
>	R-390 List <[email protected]>
>Subject: Re: [R-390] Re: UTC 68819 xfmr
>
>Hi all,  thanks for the suggestions on the transformer.  It was id'd by one
>member as 150/75000 ohms,  a transformer used in RC 47a & c (probably from 
>the
>40's or late 30's)  same as UTC 46779.  After first suggestion to do so,   
>I
>measured it as 187 ohm /75000 ohm  so am satisfied I know what it is to the
>degree I need to know (still curious why the voltage ratio didn't give the 
>exact
>impedance ratio though).  Since my first query,  I dug out three more of 
>these
>in my pile plus some other interesting input transformers including some WE
>transformers and some signal corp small xfmrs so I have a number to 
>experiment
>with and explore.  thanks to all for providing what I needed.  Dan
>
>Dave and Sharon Maples wrote:
>
> > Drew: That's an excellent technique.  I think in this case I'd be 
>inclined
> > to apply 6 VAC to the 75,000 ohm winding, and measure the other winding.
> > That way the resultant will be in the millivolt range, and the 
>transformer
> > won't pull any serious current...
> >
> > Dave WB4FUR
> >

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