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 Post subject: Thoradson T-20D80
PostPosted: Aug Thu 08, 2019 6:22 pm 
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Joined: Aug Tue 04, 2009 2:15 pm
Posts: 400
Location: Elmira, NY
I need help on lead identification. In 1947 Catalog the turns ration is listed as both 3.2:1 and 2:1. The driver xfmr has 5 leads on the primary side and 3 on the secondary. I assume the ‘red” is the center tap. The colors are faded. I tried measuring ohms to identify the combination readings are:
Ret to yellow?/black 24 ohms
Red to red/black 20 ohms
Red to green? 40 ohms
Red to green/black? 30 ohms

I’m somewhat sure one is red/black
One appears to be yellow /black
One appears to be red
The other two I’m guessing.


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 Post subject: Re: Thoradson T-20D80
PostPosted: Aug Thu 08, 2019 8:57 pm 
Member

Joined: Aug Tue 04, 2009 2:15 pm
Posts: 400
Location: Elmira, NY
Update:

Aside from the lead color I was able to determine how to connect this transformer and select correct turns ratio.

I applied a known voltage amplitude signal to the primary winding while observing the output on the secondary connections. I get exactly 1:3.2 increase on one pair, and 1:2 on the other.(Common center tap).

Trying to use logic, the ohmic readings are throwing me off; they just don't add up. It's almost like there are two separate windings with their center taps common.

My initial thought /logic was it was one continuous secondary with 5 connection points. There is continuous continuity between all connections.

Am I missing something, I'm prone to brain freeze?


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