Abstract: A resistor with a heat sink, particularly adapted for use as a current limiter in an electrical system, such as a power transmission system. The resistor comprises a hollow tube formed of metal which offers resistance to the passage of electrical current, the tube being of a length sufficient to provide the electrical resistance for a given application. The heat sink comprises a material having a high specific heat, the material being contained within the tube and adapted to absorb heat generated by the resistance of the tube to passage of electrical current.

Abstract: Our invention relates to electric heating elements for heating liquid within a tank, and particularly to heating elements for use in domestic commercial water tanks, wherein the element comprises a metal mounting member secured to the wall of the tank and a sheath portion carried by the mounting member and extending through a hole in the tank wall for immersion in the water in the tank. The sheath portion contains a resistance conductor and insulation which electrically insulates the conductor from the sheath, so that water in the tank is heated when the resistance conductor is electrically connected to a source of electrical energy.Our invention provides means for protecting the electric heating element from damage which may otherwise be caused by a sudden surge of high voltage, such as that which may be caused by lightning disturbances in the immediate vicinity.

Abstract: The method of providing a corrosion-resistant coating on the aluminum sheath of an electric immersion heater, comprising the steps of treating the sheath with a nitric acid solution to put a uniform layer of oxide on the exterior sheath surface, then treating the sheath with a caustic tin-bearing solution to strip all oxide from said exterior surface and replace it with a uniform layer of tin, then depositing a uniform layer of bronze over the tin layer, and finally depositing a layer of tin over the bronze coating.