I have a stack of 36/48v 30a linear golf cart chargers & thinking of what I could do with them. Years ago I would rewing microwave over transformera as spot welders for 18650s cells & other things, these chargers have secondary winding in a separate section so it would be easy, But they are all Ferro resonant type transformers and I don't know if they can be rewound to work properly on a different voltage or current? Anyone know why they add the FR winding a primary instead of just a transformer with 2 windings.

 

Your thread title has nothing to do with your thread question and will only mislead people who would like to help you.

 

Anyone know why they add the FR winding a primary instead of just a transformer with 2 windings.

A ferro-resonant transformer uses a capacitor on a separate output winding to nicely provide passive AC voltage regulation.

It has a primary and secondary core section with a magnetic shunt between the two.
The capacitor operates at resonance with the transformer inductance of its winding on the secondary, which saturates the secondary portion of the core at the designed operating frequency.

The primary section stays unsaturated as in a standard transformer, thus the primary magnetizing current doesn't increase when the secondary saturates, due to the magnetic shunt between the two which carries both the unsaturated and saturated flux.

The saturation of the secondary portion of the core provides a relatively constant output voltage, reducing the effect of input voltage variations on the output, since a change in the primary voltage value, along with any transients or distortion, don't significantly affect the secondary magnetic saturation value.

The transformer could likely be rewound for different input and/or output voltages. but you would need to know what you are doing.
The capacitor resonant winding would be left as is.

 

A ferro-resonant transformer uses a capacitor on a separate output winding to nicely provide passive AC voltage regulation.

It has a primary and secondary core section with a magnetic shunt between the two.
The capacitor operates at resonance with the transformer inductance of its winding on the secondary, which saturates the secondary portion of the core at the designed operating frequency.

The primary section stays unsaturated as in a standard transformer, thus the primary magnetizing current doesn't increase when the secondary saturates, due to the magnetic shunt between the two which carries both the unsaturated and saturated flux.

The saturation of the secondary portion of the core provides a relatively constant output voltage, reducing the effect of input voltage variations on the output, since a change in the primary voltage value, along with any transients or distortion, don't significantly affect the secondary magnetic saturation value.

The transformer could likely be rewound for different input and/or output voltages. but you would need to know what you are doing.
The capacitor resonant winding would be left as is.

Thanks, sounds like it would be more trouble than it's worth, but may experiment just to see actual results, as a old ham radio guy I do alot of trial and error diy projects. Your reply really helped explain why the F.M. circut was put there.

 

Crutschow gave the correct explanation, and what that tells you is that the ferro-resonant constant voltage transformer is actually quite complex. So not a simple rewind candidate.

WHAT are the specifications of the CVT output, volts and amps?? AND watts input and output????? What was the charger output voltage, actually??

 

sounds like it would be more trouble than it's worth, but may experiment just to see actual results,

You should be able to rewind the primary and/or secondary as long as you leave the winding with the capacitor as is.
Just keep the volt/turns ratio value of the primary the same.

 

Crutschow gave the correct explanation, and what that tells you is that the ferro-resonant constant voltage transformer is actually quite complex. So not a simple rewind candidate.

WHAT are the specifications of the CVT output, volts and amps?? AND watts input and output????? What was the charger output voltage, actually??

They vary the 36v were 28 amp and 48v were 25 amp, I will plug a few in to check NL voltage

 

OK! Three of the 36volt secondaries in series will provide a regulated 108 volt AC supply for all of your computers. The ultimate glitch protection scheme.