Patent Publication Number: US-7215234-B2

Title: Tap-off transformer

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a tap-off transformer, and more particularly, to a tap-off transformer using isolating walls and a winding design to increase the rated voltage of transformer. 
   2. Description of the Prior Art 
     FIG. 1A  is a cross sectional side view and  FIG. 1B  is a side view of the windings of a conventional transformer. Referring to the figures, the transformer  1  comprises a coil base  11 , a core  12  and wires  13 . The coil base  11  has isolating walls  111  placed outside of it and using isolating walls  111  to form a primary side area  14  and a secondary side area  15 . The secondary side area  15  is partitioned into a plurality of winding slots  16  by isolating walls  111  with wires  13  being winded sequentially in winding slots  16 . The coil base  11  has hollow structure for placing core  12  to form transformer  1 . The above mentioned transformer structure uses isolating walls to set up a winding slot in primary side area and a plurality of winding slots in secondary side area with wires winded sequentially and unidirectionally inside winding slots to achieve the required rated voltage of the transformer. Hence, the secondary side area (˜0V-Vout) uses multiple winding slots to provide voltage isolation, however, since voltage of every isolated slot could be varied and it tends to result in over voltage between slots, thus the characteristics of component will become unstable to cause abnormal function of the product. 
   Therefore, the prior art transformer mentioned above presents several shortcomings to be overcome. 
   In view of the above-described deficiency of prior-art transformers, after years of constant effort in research, the inventor of this invention has consequently developed and proposed a tap-off transformer. 
   SUMMARY OF THE INVENTION 
   The present invention is to provide a tap-off transformer, using isolating walls and a winding design to increase the rated voltage of transformer. 
   Another, the present invention is to provide a tap-off transformer having advantages such as higher stability, longer lifetime, lower product cost, smaller transformer size and space saving capabilities. 
   A tap-off transformer of the present invention comprises a coil base, a core and wires. The coil base has isolating walls placed outside of it and using isolating walls to form a winding slot on a primary side area and a plurality of winding slots on a secondary side area Different kinds of wires could be winded inside the plurality of winding slots. A wiring start point inside the plurality of winding slots in the secondary side area is placed on one of the isolating walls in the secondary side area, with coils starting from the start point to extend outwards to either sides of the secondary side area and ending at either sides to form two voltage segments. The coil base has a hollow structure for placing the core to form a transformer structure. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawings disclose an illustrative embodiment of the present invention which serves to exemplify the various advantages and objects hereof, and are as follows: 
       FIG. 1A  is a cross sectional side view of a conventional transformer; 
       FIG. 1B  is a side view of the windings of a conventional transformer; 
       FIG. 2A  is a cross sectional side view of a tap-off transformer in the present invention; 
       FIG. 2B  is a side view of the windings of the tap-off transformer, 
       FIG. 3  is a diagram illustrating a first embodiment of the tap-off transformer; 
       FIG. 4  is a diagram illustrating a second embodiment of the tap-off transformer; and 
       FIG. 5  is a diagram illustrating a third embodiment of the tap-off transformer. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 2A  is a cross sectional side view and  FIG. 2B  is a side view of the windings of the tap-off transformer in the present invention. Referring to these figures, the tap-off transformer  2  disclosed in the present invention comprises a coil base  21 , a core  22  and wires  23 . The coil base  21  has isolating walls  211  placed outside of it and using isolating walls  211  to form a primary side area  24  and a secondary side area  25 . A plurality of winding slots  26  are set up in primary side area  24  and secondary side area  25 . Different kinds of wires  23  could be winded inside the plurality of winding slots. A wiring start point  27  inside the plurality of winding slots  26  in secondary side area  25  is placed on one of the isolating walls  211  in secondary side area  25 , with coils starting from start point  27  to extend outwards to either sides of secondary side area  25  and ending at either sides to form two voltage segments (Vout˜0V and ˜0V-Vout) to effectively increase the rated voltage of transformer. The coil base  21  has a hollow structure  212  for placing core  22  to form tap-off transformer  2 . The present invention provides isolating walls and a winding design to increase the rated voltage of transformer and to improve the stability of transformer. 
     FIG. 3  is a diagram illustrating a first embodiment of the tap-off transformer. The tap-off transformer  2   a  with high rated voltage adopts a core that is consisted of two E-shaped core  221 . 
     FIG. 4  is a diagram illustrating a second embodiment of the tap-off transformer. The tap-off transformer  2   b  with high rated voltage adopts a core that is consisted of a C-shaped core  222  and a I-shaped core  223 . 
     FIG. 5  is a diagram illustrating a third embodiment of the tap-off transformer. The tap-off transformer  2   c  with high rated voltage adopts a core that is consisted of two U-shaped core  224 . 
   The present invention provides a tap-off transformer, which compared with other prior art transformers, is advantageous in: 
   The present invention provides a tap-off transformer, using isolating walls and a winding design to increase the rated voltage of transformer. 
   The present invention provides a tap-off transformer having advantages such as higher stability, longer lifetime, lower product cost, smaller transformer size and space saving capabilities. 
   Many changes and modifications in the above described embodiment of the invention can, of course, be carried out without departing from the scope thereof. Accordingly, to promote the progress in science and the useful arts, the invention is disclosed and is intended to be limited only by the scope of the appended claims.