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'Something different'
Author:Henry Ramsey (registered user: 2952 posts )
Date: Thu, Apr 19th, 2012 @ 23:20 ( . )

On 04/19/2012 @ 15:12, Merlin wrote :
On 04/18/2012 @ 19:27, Henry Ramsey wrote :
: Isn't there a rule of thumb to not exceed 80% of a PT ampacity?
:

: Typical power factor for a capacitor input filter is 0.65, so if a transformer is rated for 2Arms then it will probably reach its limit when you suck
: 2 * 0.65 = 1.3A rectified DC.
--

Is there any wiggle room to that 1.3A or is it set in stone like ohms law? Can I get to say 1.4A and still keep the PT happy? My current plan is to wire two 12a_7 tubes all from the same 12V off the CT.

That's 0.9A for the 12k5 heaters, 300mA combined for the 12a_7 heaters wired for 12V.

That gets me to 1.2A which leaves 100mA for the 12k5 plates/sc grid and preamp. All of which comes through the regulators if that makes any difference. The two 12k5s can draw almost twice that alone; 85mA per SC grid, 8mA per plate. Then another few mA for the preamps.

-- REPLY: [With No Quote] --- [With Quoted Text]

Replies:
--* Something different
4/20/2012 @ 04:19--Merlin
----* 11.9VDC, 6VAC at CT
4/20/2012 @ 08:35----Henry Ramsey
4/20/2012 @ 10:04------Merlin
4/20/2012 @ 16:10--------Henry Ramsey
4/21/2012 @ 09:09----------Merlin
4/21/2012 @ 10:11------------Henry Ramsey
------------* 13.32VAC across heaters
4/21/2012 @ 20:16------------Henry Ramsey
4/22/2012 @ 03:07--------------Merlin

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