Transformer, more especially a voltage dropping transformer for an electric welding machine

A transformer comprising a primary circuit including a primary winding and a secondary circuit including a secondary winding, a first plurality of electrically active cooling turns forming at least part of the secondary winding of the secondary circuit, and the number of turns of said first plurality being dependent upon the transformation ratio of the transformer, said transformer further comprising a second plurality of electrically inactive cooling turns having a cooling liquid circulating therein provided in the winding of at least one of said circuits in thermal contact with that winding for serving solely a cooling function and not forming a part of said secondary circuit, the number of turns of said second plurality depending upon the cooling to be provided, means for enabling circulation of a cooling liquid through said second plurality of cooling turns, and at least a portion of said electrically active turns and said electrically inactive turns dividing the winding of the primary circuit into separate sections.