Identifying buck-boost transformer windings?

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Imagine you are asked to install a used buck-boost transformer. Imagine you  
could normally do this in a few minutes. Except if the leads were cut short  
such that identifying characters on the leads' insulation were missing.  

Identifying 2 leads belonging to any one winding is straightforward ohm meter  
work. Maybe use of a ESR meter might help separate the X windings from the H  
windings?. But identifying which specific winding is which and which end is  

How would you go about identifying the windings? Maybe use a Variac to input  
voltage to each of the windings then measure the output of the others? What  
outputs should I expect at, for example, the H3/H4 winding with a voltage on  
H1/H2 winding? How to identify backward connection of a winding?  

Are the two H windings identical? The two X windings?  

Suggestions welcome.  

This is a 208 -> 230 (ie, 12 & 24 v buck-boost voltage) single-phase  
autotransformer in N. America.  


Re: Identifying buck-boost transformer windings?

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I have the wiring diagrams in .pdf for Square D buck/boost xmfrs. The
X wires are the heavy wires and the H wires the thin wires. X1 and X2
are the ends of one winding. X2 and X3 the ends of another winding.
The other windings are similar. Anyway, if you send me an email I'll
send you the .pdf of the wiring manual. Then you will be able to
figure out how to wire the thing. It should be easy enough, just
measure the output in one random configuration and you will be able to
tell what's what by looking at the manual.

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Re: Identifying buck-boost transformer windings?
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Have a wiring diag:

How to wire it isn't the question. Which wires are H1, H2, X1, X2, etc. is  
the question.  

Series light bulb or Variac (will use 120 mains for testing as that is the  
only Variac I have...) seems the answer.  

Remaining question: are H1/2 and H3/4 primary windings interchangeable? X1/2  
and X3/4 windings interchangeable?  


Re: Identifying buck-boost transformer windings?
On Tue, 11 Feb 2014 14:44:18 -0800, the renowned DaveC

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Say you have 8 wires. If you measure the resistance between any one
wire and any of the remaining 7 wires, what do you get?  There are 28
unique combinations (8 * 7/2):  


Wire   to      Wire    R (Ohms) ??  
A              B
A              C
A              D
A              E
A              F  
A              G
A              H
B              C
B              D
B              E
B              F
B              G
B              H
C              D
C              E
C              F
C              G
C              H
D              E
D              F
D              G
D              H
E              F
E              G
E              H
F              G
F              H
G              H  

Best regards,  
Spehro Pefhany
"it's the network..."                          "The Journey is the reward"             Info for manufacturers:
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