LOPTX's work by being tuned, you need to provide the correct tuning and just a simple high voltage pulse to make it ring - I would suggest you copy the circuit from the TV, and get all the tuning components from there as well, including the scan coils!.
Usually they are powered from 110V to 150V depending on their size!.
The three wires are:
1) Final anode (25KV)
2) Focus anode (variable - about 6KV)
3) First anode (variable - about 600V)
All the other connections are on the bottom of the transformer, you can't read from the three leads because of the internal rectifiers in the transformer.
I don't know what you're trying to do?, but I would suggest NOT doing it, they generate high voltages but are quite fragile, you are likely to damage either the TX or yourself!.