xfrmr connections

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forabit

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I have a dual winding xfrmr (.5kva). It has been removed for testing (not by me) H1 is to H3, H2 is to H4. X1 open wire label #50 X3 also #50 X2 is #49
X4 is also #49.
My Question Why would H1 go to H3 and H2 go to H4 ?. It looks like #49 goes through one set of low side windings and #50 goes through the other.
 
A dual primary device has two starts and two finishes.

The starts will be H1 and H3 and the finishes will be H2 and H4 (on the high voltage side)

You have two connection options:
Series - which is tie the finish of coil one with the start of coil two.
Add's the voltages together.

parallel - which is tie the starts of each coil together and the finishes together.
 
ok
But what I'm saying is H1 is connected to H3 and nothing else. Also H2 is connected to H4 and nothing else. So X,1,2,3,4 are the supply and load. Nothing to or from H1,2,3,4.
 
If I were to take a guess its a common 240x480-120/240 transformer.
If so if you had a 240 supply connect H1 and H3 together, H2 and H4 together and apply 240 to the H1H3 and the H2H4
If yo had a 480v supplyu connect H2 to H3 and connect the 480v to H! and H4.
Typically the secondary is wired as a 120/240 by connecting X2 and X3. The output would be 120 from X1-X2X3 and 120 X4-X2X3 and 240 fron X1-X4.
The X2X3 connection becomes a neutral point which iscommonly grounded.
Again, this is a very common configuration for transformers in that size range.
 
yes it is a common 240x480 -240x120 xfrmr. But there was "nothing" connected to any of the H1,2,3,4 wires only the X1,2,3,4 wires as stated above.
 
Thanks for the link ...but... still there is no supply connected to the primary side AT ALL.
H2 connects to H4 AND NO OTHER WIRE
H1 connects to H3 AND NO OTHER WIRE
X1 & X3 are labled the same (50)
X2 & X4 are labled the same (49)
Power only hooks up to 49 & 50
 
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If this xfmr came out of a machine tool of some sort, it was at one time the control power xfmr. Most likely (considering the H connections) it was originally connected for 208 or 240. One of two things likely happened; either the machine was reconnected for 480 and the xfmr was left connected for 240 (it happens more often than you'd think), or the xfmr was overloaded to the point it failed.

The control power is now derived from a basic 120V circuit, and the xfmr was simply disconnected and left in place. That would explain why the H leads were not connected. Quite likely, there's a fuse missing somewhere in the X circuitry, and the outside 120V was spliced in to the load side of the fuseholder.

Only one possibility here, but it fits!
 
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