[R-390] Re: UTC 68819 xfmr

Fri, 13 Dec 2002 13:11:56 -0500

Dan,

You can easily determine the unknown impedance from voltage measurements.  
Apply an AC signal of appropriate frequency  to the known winding (110 VAC 
60 Hz works well for a typical high impedance audio transformer winding).  
Measure AC voltage on secondary.  Divide this by primary voltage and square 
the result.  This gives you the impedance ratio from which you calculate the 
secondary impedance.   I have used 6.3 VAC on a low impedance winding and 
measured the resultant on the high impedance winding.  Don't apply high 
voltage to a low impedance winding or you'll let the smoke out.

Drew

>Date: Thu, 12 Dec 2002 15:35:49 -0800
>From: Dan Merz <[email protected]>
>Reply-To: [email protected]
>To: R-390 List <[email protected]>
>Subject: [R-390] UTC 68819 xfmr?
>
>Hi,  does anyone happen to know the prim/sec impedance of a UTC 68819
>transformer,  Army #2Z9986-2;  the box is marked  ?50-ohm to 75,000 ohm
>but not legible enough to make out the primary.  It's small unit about 3
>inch high,  thanks,  Dan.

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