Transformer Rating

Post the query in Electrical Engineering section for good response.

It is a low profile, single phase transformer, has two primary windings of 115 VAC, wich can be paralleled to connect to a 115VAC mains supply, or can be put in series for use on a 230VAC circuit.

It has also two secondaries and its output is around one Amp. at 9 VAC (secondaries paralelled) or 0.5 Amps at 18 VAC (secondaries in series).

Flip it over and you'll se 4 solder lugs on each side of it.

Thank you sir...

please let me know how test with this type of transformer i removed out from the PCB and it's one side has 4 pins and other side has 8 pins..

how we test with this trafo on desk using digital multimeter.

Because this is a PCB mount transformer there could be 4 of the 12 pins strictly used to physically mount the transformer to the circuit board. The remaining 8 pins would be the ends of 4 windings inside the transformer. There should be 2 coils of smaller diameter wire (primary windings) and 2 coils of larger diameter wire (secondary windings). Use your multimeter and determine if you have continuity in all 4 windings. If you do and none of the values is 0 ohms (shorted winding) the transformer is all right and if you don't (winding is open) then the transformer is faulty. The resistance values of the 2 primary windings should be equal and the secondary windings should be slightly different. I don't have one here so I cant give you actual values.

Continuing from Elroy. Take a low voltage AC source, transformer with somewhere 3 to 9 VAC output, low power. I avoid straight 110/220V on my workbench. Connect a primary or secondary to it, and measure the proportional voltages.

PC board mounted low power transformers normally are built as short circuit proof. When the test returns a good transformer, most likely the rectifier / DC regulator circuit has a short in it. That is my bet.

It is a single phase transformer which can operate at 115 or 230vac that is why it is described on the primary as 115-115.

The Primary windings should have an aprox equal high resistance probally in the 1000's of Ω if the primary windings are open circuit you would need to find a suitable replacment, but before replacing it I would suggest that you check out the bridge rectifer on the output stage for problems.

Depending on your power sypply to the system the PCB will configure the transformer to 115vac (both windings connected in parrallel) or for 230vac (both windings connected in serries).

The secondary windings work in the same way, for an output of 9vac output at 1 amp both output windings would be wired in parrallel and for 18vac at 0.5 amp windings connected in serries.

I hope you understand what I am saying. Now you should be able to examine the PCB to work out what configuration you are working with, and then when the supply and output voltages are established you could then connect the power to the system on your work bench (if you are a compident in testing live equipment) and check the voltages with a meter to see what is going on.

Cheers

Joe