06-26-2014, 09:22 PM
Murf
It is theoretically possible to see results like yours, but I have yet to see it. Typically the DC resistances of two halves of the primary in the output pushpull transformer are of the same order. It is normal for the outer half to have a bit higher resistance for obvious reaons, but not double. Well, suppose they wound primary half, then output, then the other primary half...but I never saw it.
This is why I asked of you being sure - one resistance is almost twice the other which is the case when measuring end to end and end to CT.
Now, having mused about that, the best check is what I suggested with a Variac and isol. xfmr. This will give you a good reference. Then you simply measure the output with AC voltmeter.
So, you plug isol. xfmr in AC MAINS, plug your Variac in the Isolation xfmr and connect the output of say 20V across the CT and one end. Measure the secondary output. If it is too small, make input 50V. Then connect the input V across the CT and the other end.
The output should be exactly the same.
It is theoretically possible to see results like yours, but I have yet to see it. Typically the DC resistances of two halves of the primary in the output pushpull transformer are of the same order. It is normal for the outer half to have a bit higher resistance for obvious reaons, but not double. Well, suppose they wound primary half, then output, then the other primary half...but I never saw it.
This is why I asked of you being sure - one resistance is almost twice the other which is the case when measuring end to end and end to CT.
Now, having mused about that, the best check is what I suggested with a Variac and isol. xfmr. This will give you a good reference. Then you simply measure the output with AC voltmeter.
So, you plug isol. xfmr in AC MAINS, plug your Variac in the Isolation xfmr and connect the output of say 20V across the CT and one end. Measure the secondary output. If it is too small, make input 50V. Then connect the input V across the CT and the other end.
The output should be exactly the same.
