[Amps] UTC BS-497 plate transformer
jim.thom at telus.net
Sun Mar 5 14:04:36 EST 2017
Date: Sun, 5 Mar 2017 05:43:12 +0000
From: "Fuqua, Bill L" <wlfuqu00 at uky.edu>
To: "amps at contesting.com" <amps at contesting.com>
Subject: [Amps] UTC BS-497 plate transformer
I have found a nice plate transformer, a UTC BS-497.
I can't find any specs on it. All that I can tell is that it has 2 primary windings for 110 and 120 volts and has a tapped secondary, with CT and two terminals for 3000V and 3500V.
I can't find it in any of the catalogs I have.
Would like to know the DC current and power capacities of the transformer.
TNX es 73
## Is it EI plate construction.....or tape wound ? How heavy is it. Put a temp short across the 120 vac prim...and measure the DC resistance from CT to EITHER 3 kv terminal.
Then again from CT to EITHER 3.5 kv terminal. Then put a temp short across the 2 x 3.5 kv terminals..... then measure the DC resistance across the 110 winding...then again for the 120 vac winding..... both are probably referenced to
a 0 terminal. IE: 0-110 and 0-120. Measure between 0 + 110....then again between 0+ 120.
## Knowing the weight and the dc resistance on the sec will tell us..usually, every thing we need to know. What you have is called a 7000 v, CT xfmr. Turns ratio is 7000 / 120 = 58.33 Turns ratio is also 7000 / 110 = 63.63
With a turns ratio that high, the max dc current you can draw will be limited...but that depends on weight. In contrast, my drake L4B xfmr has a 900 vac sec and a 240 pri. 900 / 240 = 3.75 for the turns ratio.
## Ancient hammond plate xfmrs of the 80 lb variety, would have pri taps at 0-105-110-115-120 Sec is typ 3450-0-3450 They were designed for choke input..and would deliver 3 kv under a CCS load of 500 ma. 750 ma with a 50% duty cycle = ICAS rating. They were rated at 2.2 kva CCS.
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