Determine the input voltage of the rcore transformer

Determine the input voltage of the rcore transformer. Hello everyone, I have an Rcore transformer that I want to use for an audio preamplifier circuit. I have determined the secondary and primary wire groups by measuring the resistance of the wire groups. However, I cannot determine whether the transformer is a 220v or 100v input. We hope to help
 

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make a diagram of coils showing the lead wire colors and then measure dc resistance,
i suspect the two orange wires are secondary wires,, inject 6vac on them and measure the voltages on the other side,
that should give you an idea about your traffo...
 
The 2 orange wires with higher resistance are the primary wires. The problem here is that I don't know whether I need to supply voltage to the two orange wires, 220V or 100V. In Vietnam 🇻🇳, we often remove Rcore from Japanese and European medical devices.
 
A 220V transformer can operate at 100V and output less than half the voltage. However, the 100V transformer will be damaged if it is connected to 220V mains.

To determine if it's a 220V transformer, you'll need to estimate its AV rating based on its size and weight. Connect an incandescent bulb about the same wattage in series to the primary winding and connect it to the 220V mains. If the bulb continues to light up without dimming, it should be a 100V transformer.
 
Please tell me more, is there any document or website that teaches how to wrap rcore as well as rcore conventions? I see that on rcore plastic frames there are often symbols like r6 r20 r50 (I guess the capacity symbol). Thank you so much everyone