Need to know pin out (input and output voltage rating) of a UPS transformer (image+)

I have a transformer of an old UPS, brand name was printed in cover which is missing. I just need to know how I can find out it's input and output with voltage rating. I have an image bellow:


Please help.

prohor said:

I have a transformer of an old UPS

Click to expand...

Implying it steps up 12V (24V) to mains ACV. A clever designer might (for all we know) install more windings to step down mains AC to charge the battery pack.

It will require a lot of testing, if you wish to figure out step up/down ratios, etc.

Take ohm readings. Make a list of all windings. Label leads. Find where you have 3 leads connected, or 2 connected. (3 connected leads is most likely a center-tap.)

It should be okay to apply low voltage AC. (Do not apply high voltage AC.) 50 or 60 Hertz is probably the design frequency. Energize one winding, and take readings to see if other windings step up or down. When done testing, ramp down the waveform to zero amplitude, rather than disconnect it suddenly.

Does low ohms necessarily mean it's a low voltage winding, and high ohms mean high voltage? This doesn't necessarily follow when stepping low voltage up to high voltage.

u better use variac (variable ac supply starting from 1v to 120v/220v).sometimes u have to join other wires like yellow and grey ( e.g as shown on your picture) to make a centre tap.also google transformer colour coding.