Identifying the Transformer

frmalura

nameplate contains all details like type of winding,no of core,vector group etc you cannot cheque these technical details .so wiothout nameplate it is impossible to identify the transformer.

Are you sure it is a step down transformer. It can be used as a step up trafo as well.

Try laying your hands on a data sheet, test certificates/ reports.

Hi,

At least can you guess weather it is a power transformer / control transformer or Isolation transformer ? What is the approximate size and weight? Is it single phase or three phase? From the terminal connections can you guess what is the voltage range of primary / secondary ( low /medium or High Voltage)? Could you check up the resistance of the windings and any possibility of knowing the gauge of the wires ? These are few of the information required to make at least a wild guesses. Sorry I am helpless to give any satisfactory answer to your question with out more information.

well it was small medium size may b upto 100VA. its single phase transformer. Other thing is its step down transformer.. i can guess input voltage of range may be 110 volts or 220 volts.. but hw to exactly find it.. i fear to connect it to direct 220 volt supply..

If this is a large power transformer, a "wild guess" could easily wind up killing someone. No name plate, send it off to the recycler...

If the transformer is usable on your main supply (not for some "foreign" system, the middle of a complex control network or an inverter) you will have 90% chance with this approach of a goer.

First look, is there a conventional E & I lamination core with all windings on the (double width) tongue ? If not put it to one side.

Second, look for a magnetic shunt, some laminations across the winding window separating two winding. If you find one put it to one side.

Third, list the winding connections, sort out the resistance of each and note there may be an electrostatic/Faraday shield with only one connection.

Fourth, estimate (factor of two) wattage. Look at a catalogue, compare size or weight. Alternatively measure tongue-width and height of lamination stack; 50 times the (area WXH in sq")squared gives a conservative figure for watts.

Fifth, look where the leads exit the winding, they come out right next to the winding. The primary is usually closest to the core; that is for an interleaved, layer wound transformer. Bobbin wound transformers frequently have a divider, you might see multiple secondaries but there can be paired (110/220V) primaries.

Sixth,note the winding resistance of your possible primary. You should find it 1to5% of the resistance of a mains load of the estimated wattage.

S

I think your Transformer is Optimus Prime. It might be kinda hard to find.

since u are sure its a step down transformer,on no-load ,apply lower voltage to the one side(A)and see what u get at output,side(B).reverse the action on the other side(B) and see what u get again on side(A),if u apply say 220v on side A and gets say 110v on side B,if u reverse and apply 220v on side B and u get 110v on side A,side a is the primary while side B is the secondary.

While u carry out this test,makesure there is a breaker installed before the input supply to the transformer(ie output of breaker supplies the transformer).As u test check heating(temperature) of transformer,this helps to tell if voltage is too low or okay or too high.

You may go up to 380-400 and check your output if u will get 220v-230v or other voltage values that can be useful to u if its more like a power transformer.

However,the size and weght of the transformer matters a lot in this discussion.the output may also have more tappings by visaul observation.Could yr trasformer be a small one for toys or electronic controls?

Patrick Whowha

A lot of transformers are specifically wound for a specified job, the variables are limitless. If your not sure what it was originally in/for I would get rid, or you could use it for a low power choke, I once used a throw away transformer for suppressing alternator whine on my comms equipment in the car, it worked better than anything form Halfords!