Hi.
I need help to identify this transformer. I think is a output transformer.
Please see the pictures.

Many thanks.
Vriendelijke groeten,

Carlos

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From PORTUGAL, with regards
Carlos

Seems to be an impedance transformator, used e.g. in 100 or 70 volt loudspeaker distribution systems.
Today power selection is choosen at the primary side with only a few speaker impedances at secondary e.g. 4 and 8 Ohms. In early systems power selection was done in secondary circuit.

turn ratios between the several connections can be calculated by putting an AC voltage (e.g. 6.3V of a filement winding) to one of the high ohmic coils. Simple measure the voltage over the other connections. The ratio is the ratio of in- (6.3V) and output-voltages.

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De techniek was in de jaren 40 veel verder dan menigeen zich bewust is

Hi.
Many thanks, to both, for the answers.

I put 10 volts in the the winding of lower resistance and got the following results.

Can you help me to calculate the ratio.

Many thanks.
Vriendelijke groeten,

Carlos

--
From PORTUGAL, with regards
Carlos

The ratio of turns is identical to the ratio in voltages.
I.e. a voltage ratio 100V to 10V means a turns ratio of 10 to 1.
For the impedance transformation you have to calculate the square of the turns ratio.
I.e a turns ratio of ten means an impedance ratio of 100.
Given the ratios you measured I think it is right to say it is line transformer for 70/100V public address (PA) systems.

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De techniek was in de jaren 40 veel verder dan menigeen zich bewust is

Hello.

Many thanks for your help.
The explanation is very good and now I understand perfectly.

Best regards.

Carlos

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From PORTUGAL, with regards
Carlos