| 摘要 |
<p>The object of the proposed process is to inhibit the tendency to thermal runaway in a metal oxide variator which has to pass full load current for extended periods. A satisfactory stabilisation of the material is achieved by coating the whole external surface of the varistor element with silver and then heating it to a temperature in excess of 500 deg.C for a length of time. During this process the silver is diffused into the outer regions of the metal oxide. The process may be extended to include the production, simultaneously with the coating and diffusion, of electrical contact surfaces on the varistor. These surfaces have a thicker layer of silver. Alternatively the contact surfaces can be added in a further manufacturing stage.</p> |
