During May, 1910, the U. S. Bureau of Standards issued a circular showing that each watt saving in core losses was a saving of 88 cents, which is evident economy in the use of high grade transformers.
Copper Losses.—Since the primary and secondary windings of a transformer have resistance, some of the energy supplied will be lost by heating the copper. The amount of this loss is proportional to square of the current, and is usually spoken of as the I2R loss.
Figs. 1,949 to 1,953.—Westinghouse low tension transformer connectors for connecting the low tension leads to the feeder wires. The transformers of the smaller capacities have knuckle joint connectors and those of the larger sizes have interleaved connectors. These connectors form a mechanically strong joint of high current carrying capacity. Since the high tension leads are connected directly to the cut out or fuse blocks, connectors are not required on these leads. The use of these connectors allows a transformer to be removed and another of the same or a different capacity substituted usually without soldering or unsoldering a joint. The connectors also facilitate changes in the low tension connections.
Ques. Define the copper losses.
Ans. The copper losses are the sum of the I2R losses of both the primary and secondary windings, and the eddy current loss in the conductors.
Ques. Is the eddy current loss in the conductors large?
Ans. No, it is very small and may be disregarded, so that the sum of the I2R losses of primary and secondary can be taken as the total copper loss for practical purposes.
Ques. What effect has the power factor on the copper losses?