求翻译：以上是单一接法的优点，一般变压器至少有两个绕组，因此变压器有几种接法的组合。是什么意思？

These are the advantages of a single connection, usually at least two transformer windings, so there are several transformers connected in combination.

It is more than a single connection for the advantages of a general transformers, there are at least two winding transformers, therefore there are several combinations of the law.

The transformer copper loss refers to the loss which at the beginning of the secondary wire DC resistance creates, therefore only needs the transformer on to add on the nominal current then, the concrete operation is the secondary coil direct pipe nipple, adds the voltage on a side, amounts to until

These are the advantages of the single-connection, generally at least two windings of transformers, transformers have several connections of combination.

These are the advantages of the single-connection, generally at least two windings of transformers, transformers have several connections of combination.