With two primaries, if they are connected correctly in series, the inductance will be four times one primary inductance. Connected wrong, the inductance will approach zero.
If you connect the primary series pair -- in series with an incandescent bulb, incorrectly connected will make the bulb very bright. Correctly will be dimmer.
If you have an inductance meter, it's easier.
Jn
If you connect the primary series pair -- in series with an incandescent bulb, incorrectly connected will make the bulb very bright. Correctly will be dimmer.
If you have an inductance meter, it's easier.
Jn
Why a need for an inductance meter ?
A simple DMM is all you need.
You power the trafo, then measure the two secondaries not connected with DMM on AC voltage mode.
Then, power off, then connect the secondaries in serie. There are two ways to do it, do it one way or the other.
Then, power the trafo and measure what you get. If double the previous measurement, everything is ok for a center tap operation.
If you get near OV, then you should connect the secondaries, the other way.
A simple DMM is all you need.
You power the trafo, then measure the two secondaries not connected with DMM on AC voltage mode.
Then, power off, then connect the secondaries in serie. There are two ways to do it, do it one way or the other.
Then, power the trafo and measure what you get. If double the previous measurement, everything is ok for a center tap operation.
If you get near OV, then you should connect the secondaries, the other way.
So I used the lcr meter and found out they were indeed coupled wrong, it's working just fine now.
No turns working against each other.
No turns working against each other.
Your procedure is perfect for phasing of the secondaries. His issue was primary phasing.
He could have also driven one secondary with a small transformer, say 5 volts AC, and used your method to discern the primary phasing.
Jn
Use an incandescent lamp instead of a fuse. A 40-75W rated is suited for most of devices.