Re: center tapped power transformer help needed

[John Robertson]

On 05/03/2016 8:51 PM, Jim Brain wrote:

On 5/3/2016 10:48 PM, Chuck Guzis wrote:

On 05/03/2016 08:08 PM, Jim Brain wrote:
60 Hz?  Maybe you could give the guys at Prem Magnetics a call. They're
always sending emails offering to do custom work.

http://www.premmagnetics.com/

Yep, 50/60Hz.  I will check them out.

Also, Ian, thanks for the link.  I'll check them out as well.  I will 
admit, though, those Xformers looks huge in the brochure, and I always 
thought those little 120->6.3V 6VA transformers I used to find in 
cannibalized tape recorders and such were so much smaller.


Jim


Nothing stopping you from using two smaller transformers - 120 primary 
to some secondary voltage, say 24VAC, then a second transformer with a 
240V CT primary that also has a 24VAC secondary. Assuming you get the VA 
figured out correctly these should work and be much smaller than a 
single 240CT to 120VAC transformer.


Hammond Manufacturing makes a wide range of superior quality 
transformers that is widely used by the tube and regular electronics folk.


https://www.hammfg.com/electronics/transformers/power/186-187

I think you will find this series helpful, note the VA rating and get 
yourself one of the 187C20 and a 186C20 - or for a bit extra power and 
to allow for losses, get the 187D20 and 186D20 - wire the 24VAC 
secondaries together (ignoring the centre tap on the secondaries of 
course). Farily compact.


Hammond also will wind you a single or a thousand transformers...I like 
looking at their complete line, including a replacement transformer for 
the early 1920s RCA Radiola III battery radio.


https://www.hammfg.com/electronics/transformers/classic/118944

Amazing range!

https://www.hammfg.com/electronics/transformers/classic/zone

John :-#)#


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Re: center tapped power transformer help needed

[Jim Brain]

On 5/3/2016 10:48 PM, Chuck Guzis wrote:

On 05/03/2016 08:08 PM, Jim Brain wrote:
60 Hz?  Maybe you could give the guys at Prem Magnetics a call.  They're
always sending emails offering to do custom work.

http://www.premmagnetics.com/

Yep, 50/60Hz.  I will check them out.

Also, Ian, thanks for the link.  I'll check them out as well.  I will 
admit, though, those Xformers looks huge in the brochure, and I always 
thought those little 120->6.3V 6VA transformers I used to find in 
cannibalized tape recorders and such were so much smaller.


Jim

Re: center tapped power transformer help needed

[Chuck Guzis]

On 05/03/2016 08:08 PM, Jim Brain wrote:
> Anyone here do any transformer specification or design and would be 
> interested in some consulting dollars to help me source/create a
> weird transformer option?
> 
> What I need is a 12V primary, 12V:12V center tapped secondary that
> can support 12VA of power.  Higher voltages are OK, but not needed.
> I am struggling on the Xformer details, but I know it needs to be
> center tapped, 1:1:1 @12VA

60 Hz?  Maybe you could give the guys at Prem Magnetics a call.  They're
always sending emails offering to do custom work.

http://www.premmagnetics.com/

Re: center tapped power transformer help needed

[Ian McLaughlin]

Why not use a 240v CT to 120v ?  Maybe something like this?

http://www.signaltransformer.com/sites/all/pdf/A41.pdf 


Use the 240v side as your 12-0-12 and the 120v side as your 12v.

Ian

> On May 3, 2016, at 8:08 PM, Jim Brain  wrote:
> 
> Anyone here do any transformer specification or design and would be 
> interested in some consulting dollars to help me source/create a weird 
> transformer option?
> 
> What I need is a 12V primary, 12V:12V center tapped secondary that can 
> support 12VA of power.  Higher voltages are OK, but not needed.  I am 
> struggling on the Xformer details, but I know it needs to be center tapped, 
> 1:1:1 @12VA
> 
> Jim
> 
> -- 
> Jim Brain
> br...@jbrain.com
> www.jbrain.com
> 
> 
> 
> ---
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center tapped power transformer help needed

[Jim Brain]

Anyone here do any transformer specification or design and would be 
interested in some consulting dollars to help me source/create a weird 
transformer option?


What I need is a 12V primary, 12V:12V center tapped secondary that can 
support 12VA of power.  Higher voltages are OK, but not needed.  I am 
struggling on the Xformer details, but I know it needs to be center 
tapped, 1:1:1 @12VA


Jim

--
Jim Brain
br...@jbrain.com
www.jbrain.com