Shadow Meter Question - Printable Version

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Shadow Meter Question - joybird - 05-10-2016

What was the correct DC ohms of a good coil on these??


I have been told 900 ohms 1000 ohms 1500 ohms

I have one from a Philco Model 17 and the coil checks out good at 670 DC ohms.

one from a Model 16 125-126 45-2028 OPEN COIL
one from a Model 650 45-2086 OPEN COIL

All the links I find leaves it up in the Air. Nothing as to what Philco intended them to be in DC ohms


Any Help appreciated

Bob T

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RE: Shadow Meter Question - morzh - 05-10-2016

1. 1000 feet of #40 gauge enameled copper wire will be needed to rewind the coil in the Shadow Meter assembly. It just so happens that #40 gauge wire has a resistance of about 1.1 ohms per foot. So in a typical radio, a current draw of 10ma. will give the 10 volt drop across the coil that it takes to operate the shadow vane correctly.

(calculates at 1,100 Ohms)




http://www.philcorepairbench.com/tips/svctip01.htm

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RE: Shadow Meter Question - joybird - 05-10-2016

Yes Thank You

I did find an original that measured 960 ohms, so that is close enough.

Bob T

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RE: Shadow Meter Question - joybird - 05-21-2016

Found another P/N 6497 Original from early 16B
Coil measures 848 DC Ohms

Functions well, not tried in Radio.



Bob T

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RE: Shadow Meter Question - morzh - 05-21-2016

As long as it functions well, plus minus 20% or so does not matter. It is a DC magnet, they are way simpler and not critical to things like a turn short.

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