Vegetable oil cooled high-voltage transformer <a rel="nofollow" class="external autonumber" href="https://www.siemens.com/about/sustainability/en/core-topics/innovation/references/vegetable-oil-transformer.htm">[3]</a>
<a href="//commons.wikimedia.org/wiki/User:Ikar.us" title="User:Ikar.us">Ikar.us</a>
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