Wires triple-insulated

Figure 3-25 Off-line transformer using triple-insulated wire.

Another method to meet the safety specifications is the use of triple-insulated wire for the secondary windings. Its use can reduce the transformer s size and leakage inductance compared to the border-tape method. Triple-insulated wire has three distinct, approved layers of insulation and it may be wound directly in contact with the primary windings. Whether Mylar tape is needed in or around the transformer depends upon the insulation system used in its construction. This type of transformer can be seen in Figure 3-25. 

AI2O3 furnace 4.5 kW power, super Kanthal heating wires, triple insulation. vacuum-tight reaction chamber... 

A. Sebaconitrile. A 3-1. three-necked flask (Note 1), equipped with a mechanical stirrer (Notes 2 and 3) and a thermometer which dips into the liquid, is heated in an oil bath to 160°. In the flask are placed 505 g. (2.5 moles) of commercial sebacic acid (Note 4) and 180 g. (3 moles) of urea (Note 5), and the melt is heated with stirring for 4 hours at about 160° (Note 6). The oil bath is removed, the surplus oil is wiped off, the flask is insulated (Note 7), and the temperature is then raised, as rapidly as foaming permits, to 220° by means of a triple burner and wire gauze. It is important to continue the stirring for at least 5 minutes after 220° is attained otherwise the mass will foam over during the subsequent distillation. 

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