Since NGK insulators were mentioned in your Jan. issue, I thought the following might be interesting to your readers.

NGK (Nippon Gaishi Kaisha, Ltd.) insulators are manufactured by NGK Insulators, Ltd. of Mizuho, Nagoya, Japan. The company was formed in 1919, and their first export of insulators to the United States was in 1930. In 1965 NGK Insulators of America, Ltd. was established in the United States. Since 1965 many American electric companies have been using NGK insulators. Today NGK is the world's largest insulator manufacturer, with products shipped on a world wide basis.

The company has four factories involved in the production of insulators, one of which (at Mizuho, Nagoya), produces pin and small suspension insulators. The plant at Komaki, Komaki produces standard and fog type suspension insulators. The remaining two plants produce other types of insulators, line hardware, special application ceramics and metals, chemical process porcelain equipment (pumps and valves), and water and sewage treatment equipment.

The NGK trade mark (fig. 1) was designed by combining the "Star Delta" mark which symbolizes a transmission line, with the rising sun, a symbol of Japan. Generally, the insulators carry this trade mark, NGK, Japan, and the last two digits of the year of manufacture. 

The trade mark (fig. 2) may appear on small insulators indicating the insulator was made by a subsidiary. At the request of certain buyers, Japan, NGK, Fig. 2 and/or the year may be omitted from the insulator. On certain specialized insulators, only the word Japan may be present. NGK insulators come in three standard colors: gray, brown, blue.

I have a few porcelain insulators like that on page 23 of the Jan. issue that have been removed from transformers and voltage regulators. They are both one and two piece models and have copper or brass fittings on the inside to which the line wire was attached.

Kenneth Schumacher