208V to 208/120 transformer

You get 208 volts coming in via an L6-XXP plug. Output is an isolated
120/208 volt split phase. So how would this be done?

http://www.apcc.com/products/resourc...se_sku=SURT003

One possible idea is:

|<------- 208V input ------->|
| |
* *
\/\/\/\/\/\/\/\/\/\/\/\/\/\/
===================================
/\ /\/\/\/\/\/\/\ /\/\/\/\/\/\/\ /\
* * * * *
| | | | |
A B C D E

A-C = 120V
C-E = 120V
B-D = 208V
A-E = 240V

C might even be bonded to ground.

Another possibility is that it is not really 120/208, but some compromise
voltage like 112/224 output (so they don't have so many transformer taps).

How would I be able to determine exactly what they are doing? They do not
seem to provide schematics for anything.

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------

On Fri, 25 Dec 2009 11:50:26 +0000, Stephen Furley
<(E-Mail Removed)> wrote:

>
>
>
>On 21/12/09 20:25, in article (E-Mail Removed),
>"phil-news-(E-Mail Removed)" <phil-news-(E-Mail Removed)> wrote:
>
>> You get 208 volts coming in via an L6-XXP plug. Output is an isolated
>> 120/208 volt split phase. So how would this be done?
>>
>> http://www.apcc.com/products/resourc...?base_sku=SURT
>> 003
>>
>> One possible idea is:
>>
>> |<------- 208V input ------->|
>> | |
>> * *
>> \/\/\/\/\/\/\/\/\/\/\/\/\/\/
>> ===================================
>> /\ /\/\/\/\/\/\/\ /\/\/\/\/\/\/\ /\
>> * * * * *
>> | | | | |
>> A B C D E
>>
>> A-C = 120V
>> C-E = 120V
>> B-D = 208V
>> A-E = 240V
>>
>> C might even be bonded to ground.
>>
>> Another possibility is that it is not really 120/208, but some compromise
>> voltage like 112/224 output (so they don't have so many transformer taps).
>>
>> How would I be able to determine exactly what they are doing? They do not
>> seem to provide schematics for anything.
>
>I downloaded the manual, but you're right, it doesn't tell me great deal.
>It does say that there's an input selector switch for 208 or 240 V, so there
>must be an extra primary tap, but that's not really relevant to your
>question.

Actually, it may well be relevant. 208V output may only be available
with 208V input. IOW, only a center tap on the secondary (no
connections B&D).

<snip>