I have a nice little 120VAC to 7.5KV transformer that used to call an air purifier its home, but I'm not sure how to wire it. I have some guesses, but I want to make sure I don't burn down my house so I am hoping to verify them with the help of the yahoo answers community.
Transformers consist of a primary and secondary winding. If you are certain of the AC input side (and the fact that they are black and white suggest you are) then the green and red wires are the secondary and would produce the 7.5kv AC output. Neither of these wires can be connected to ground as that would short the transformer and more than likely fry it,trip a circuit breaker , cause a fire or all three. Secondary windings with more than two connecting wires would indicate a transformer that can be tapped, which means that various voltages can be obtained depending on the combination of the output wires. 7.5 KV is a very dangerous output and if you are using the transformer outside of it's intended device, a fuse on one of the AC leads would be an absolute necessity.
Do you have a volt/ohm meter? If you do, with the transformer unplugged from any AC source, take the ohm meter and measure the amount of resistance in the black/white AC input leads; then see if there's continuity between those wires and the long white wire coming off the same side of the transformer as the AC input leads. Then take the ohm meter and measure the resistance between the single output lead and the green wire. Also check to see if there is a meter reading between the output lead and the AC input wires. If there's readings between all transformer wires, you probable have what is called an Auto-transformer. The output is tapped from one secondary winding common to both AC input and HV output. Did you take the manufacture name and model number off the transformer and do an Internet search to see if there might be an online circuit diagram? ------------------ If all else fails, make sure that all the wires from the transformer are not accidentally touching or anything and that they are situated well apart from one another, then hook up AC voltage into the transformer. Don't attempt to measure any voltages with your meter. Most likely it will not read voltage that high. Be very careful, the voltages on that transformer can HURT YOU seriously. Do not fool with the transformer leads with AC voltage applied to it. Plug in the AC voltage and observe the transformer. If nothing starts popping and smoking, it probably functining alright. Unplug the AC from the transformer. Even if the transformer was defective and shorted out internally, all it would do is cause a circuit breaker in your house to kick off. Simple matter of disconnecting the AC from the transformer and then reseting the circuit breaker. Be careful. That thing isn't a toy, and if you don't understand what your doing, that thing will hurt you or worse.
