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THE AM BULLETIN BOARD => Technical Forum => Topic started by: 4cx250 on November 16, 2010, 02:52:03 PM



Title: Can I use?
Post by: 4cx250 on November 16, 2010, 02:52:03 PM
Hello All!

     Filiment transformers are getting harder to find, so, can I use a 12 volt transformer from a battery charger, with the input on a variac turned down to make my 4-400 happy?

     The 6 volt winding would be my C.T.

     Will it work? Does the ct need to be insulated better?

Tnx,


Title: Re: Can I use?
Post by: WD8BIL on November 16, 2010, 02:57:26 PM
It should work. One thing to watch is the primary current. If that stays manageable you're good to go!
 


Title: Re: Can I use?
Post by: WA1GFZ on November 16, 2010, 07:21:58 PM
CT lead is usually smaller gauge. Better to use the full secondary winding and variac it down.


Title: Re: Can I use?
Post by: W2PFY on November 17, 2010, 12:49:07 PM
There are some 6.3 volt filament transformers on ebay that would do the job and may
help avoid an accidental application of high voltage to the filament. If you find one that doesn't have a center tap you could use another 6.3 volt transformer that's rated for about 3 amps hooked up to the non center taped transformer as the center tap. The output from that transformer could be rectified and and used for other purposes in the transmitter.   


Title: Re: Can I use?
Post by: Detroit47 on November 17, 2010, 04:42:32 PM
I just got one at Fair Radio for $67.50.
https://www.fairradio.com/catalog.php?mode=viewitem&item=7126

73 N8QPC
AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands