IN PRACTICE

摘要

The obvious way is to read what's printed on the transformer, but often the information is incomplete, so let's assume this transformer is a complete mystery. The 'six-pack test' will give you a first guess at the power rating, to see whether the transformer deserves any further attention. Rule of thumb: size of a six-pack = 500 watts, size of a 12-pack = 1500 watts, too heavy to lift = 2500+ watts! This of course is very variable, and older transformers tend to be bigger and heavier for their power rating than modern ones. The next step is to identify the windings. Using an ohm-meter, work your way around the tags or wire ends to identify which wires are connected to which others. Use bits of masking tape to label the ends of the wires, and label all the wires of the first winding as 'A', all the wires of the second winding as 'B' and so on. Check that all wires with the same label are connected, and that all wires with different labels are not connected - this will become very important when you apply power to the transformer.