Abstract: The invention relates to a novel method of producing a resistor device comprising a PTC-polymer element 2 and a varistor element 4. Both elements are molded in a common molding process using one common mold. Preferred is co-injection molding. The invention further relates to the resistor device thus produced and a current limit means including the resistor device and a switch (FIG. 4).

Abstract: The invention relates to a novel method of producing a resistor device comprising a PTC-polymer element 2 and a varistor element 4. Both elements are moulded in a common moulding process using one common mould. Preferred is co-injection moulding. The invention further relates to the resistor device thus produced and a current limit means including the resistor device and a switch (FIG. 4).

Abstract: A protective element for protecting in particular an electric motor against overload currents includes in a polymer matrix, preferably ETFE, for example 40% (by volume) of a first powdered filler of a conductive material, preferably TiB2, so that, as in the case of a PTC element, the resistance increases abruptly at a switching temperature corresponding to the melting temperature of the polymer. Also added are 20% (by volume) of a second powdered filler, a phase transition material which, at a critical temperature below the switching temperature, undergoes a phase transition in which it absorbs heat of transformation. As a result, the response time (T) of the protective element is notably extended in a range of the overload current factor (F) corresponding to higher permissible motor starting currents.

Abstract: A power switching apparatus is disclosed which has an electrical conductor to which high voltage can be applied. A series of circuits formed by a switching point and a current-limiting element which contains PTC thermistors and varistors is arranged in the cable run of the electrical conductor. An apparatus for operating the switching point interacts with the current-limiting element. The current-limiting element has n (where n is a natural number greater than 1) series-connected parallel circuits each having at least one PTC thermistor and at least one varistor connected in parallel with it. A current sensor arranged in the cable run of the electrical conductor or those connections of one of the PTC thermistors and of the varistor connected in parallel with it which are interconnected at two junction points in one of the parallel circuits are operatively connected to the input of the operating apparatus.

Abstract: A catalytic powder for coating an anode consisting essentially of 2-45 mol % of RuO.sub.2, 2-45 mol % of IrO.sub.2 and 10-96 mol % of SnO.sub.2. The powder has a rutile crystal type, at least partially as a mixed oxide and has uniform lattice parameters which lie between the values of RuO.sub.2 and IrO.sub.2 and the value of SnO.sub.2. This catalytic powder is prepared by treating H.sub.2 IrCl.sub.6.m H.sub.2 O, RuCl.sub.3.n H.sub.2 O and SnCl.sub.2, wherein m is between 4.1 and 5.5 and n is between 2.5 and 3.85, with an alcohol. The resulting solution is then evaporated. The powder obtained is dried and ignited for 1/2 to 6 hours between 400.degree.-500.degree. C. and then cooled.