| 摘要 |
<p>PURPOSE: To prevent dielectric breakdown between primary and secondary windings by housing a first box in which a primary winding and a secondary winding are insulated by injecting a synthetic resin and a magnetic flux return circuit into a second box. CONSTITUTION: A center magnetic pole core 2 is inserted in a center portion of a small coil frame 10, and a primary winding 11 is wound around the outer periphery of the small coil frame 10. A small coil frame 20 supporting a secondary winding 21 is disposed on the outer periphery of the primary small coil frame 10. This entire structure is housed in a first box 40 made of plastic. For realizing electric insulation, a synthetic resin 42 having good dielectric properties is injected into the first box 40. Then, magnetic flux return circuits 3 and 4 are arranged to surround the outer periphery of the first box 40. The first box 40 is put in a second box 50, and a synthetic resin 51 having good thermal conductivity is injected in the second box 50. As a result, the synthetic resin 51 is adaptable to deformation of the magnetic circuit due to overheat, without causing breakdown of the insulation of the secondary winding 21 formed by the synthetic resin 42.</p> |
