Repurposing a Round Iron

Started by petemoore, February 09, 2015, 11:34:20 PM

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petemoore

 It's been laying around here, an ATT it came from a similar source as this one:

http://www.ebay.com/itm/Pioneer-A9-Amplifier-Power-Transformer-ATT-759-Bando-FREE-SHIPPING-/321665121242?pt=LH_DefaultDomain_0&hash=item4ae4bc3bda

From an old Pioneer reciever.
I don't have a scale but ballpark it at about 30+Lbs, huge [approx 7'' x 7'' cylinder]
It is the most similar piece, and only info I could find, looks like what I have, but the one I have here either has different [but similar [94v 46v and 7.6v] voltage taps, or one of our meters doesn't agree with the other.
The 7.6vac tap is currently running into an FWR and filtering [with huge, heatsinked diode bridge and very large 22,000 that I also salvaged with the transformer.
I'd love to have a ballpark current limit to stay under, but I don't have a clue what the 7.6 was used for [lights..switching...I dunno].
It currently seems quiet and happy to power my 20ohm heating coil, but I might like to experiment with lower ohmage, at the same time like to not cause overload.
Is there a ballpark 'sag' under load, a voltage drop between unloaded and loaded supply that could be used as a ballpark current limit reference?
Convention creates following, following creates convention.

PRR

I'll take a wild guess and say "don't worry".

This lump must be good for well over 100 Watts, and you are sucking 3 Watts. I bet you could sag it WAY down and still not have enough heat to hurt.

20% sag on one winding is fine.

50% sag may not hurt, and at 50% sag you probably want something less saggy anyway.
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petemoore

  It's worth it just to see whether it works for something, either way is an improvement to have it sitting around waiting for an application.
  The big caps drain right down and lean on the FWR with load.
  I thought about just running AC through the kanthal wire, less heat loss etc. but at least the caps help out for about second.
  Another option I considered was tapping the ~15Vac secondary, making it a regulated DC supply, upping the ohms of the coil to reduce load.
  Another option I considered was to rectify/filter and regulate the 15vac tap, adjust this DC supply until it is just above a charged battery pack under load [choose some optimal charge voltage to set the regulator to]. This way the battery pack, and the supply would be common share the current load, a separate switch disconnects the supply from the batteries for recovery and recharge.

 
 
Convention creates following, following creates convention.