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I reclaimed a transformer from an old scrap inverter. It is a Juta 150 W inverter similar to the one below

enter image description here

The transformer have absolutely no information on it, so it is difficult to know what wattage I can expect from it. I have tested the transformer, with 220VAC on the primary (which was the secondary for the inverter, it is two yellow wires). The secondary, which has two black wires, one on the left and one on the right, and one red wire which is a center tap) have the following output voltages:

  • Between the center tap, any of the two black wires I get 12VAC,

  • Between the the two black wires I get 24VAC.

Is it safe to say the maximum power I can draw from the transformer is 150W, or is there other components inside the transformer that limits the amount of power that can be drawn from it. Does any one actually know what transformer it is and what the real value is.

Lastly, if any one came across this transformers before, there are two greyish white wires that come out of the transformer between the two yellow wires which I now use as primary. I do not get any voltage from it, and the resistance is 133 kilo ohms. Any one have any idea what those wires might be

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  • \$\begingroup\$ Just taking a wild guess here: 150 watts. \$\endgroup\$ – JRE Jan 21 at 8:16
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    \$\begingroup\$ The grey wires might be some sort of temperature sensor. \$\endgroup\$ – Finbarr Jan 21 at 11:53
  • \$\begingroup\$ At 50/60 Hz, the transformer must store energy for 1/2 cycle??? Thus a weight of the CORE will determine the energy capability. \$\endgroup\$ – analogsystemsrf Jan 21 at 16:34
  • \$\begingroup\$ @analogsystemsrf that is a quite interesting comment. Would be nice if you could formulate an answer with that info \$\endgroup\$ – rock-on Jan 21 at 17:40
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    \$\begingroup\$ You could check for some types of thermal sensor by warming the transformer up in your oven and metering for resistance change on the grey white wire. If you desire to push the transformer to it's limits, a thermal sensor would be very useful to you. Also check the wire guage and resistance of the primary and secondary windings to help you set an absolute maximum current and also get an idea of power dissipation. Exactly how much power you can get out of it will depend on the weakest link between these things and it's magnetic circuit. \$\endgroup\$ – K H Jan 21 at 21:08

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