Abstract: An actuator has an actuating element and an actuating drive with an electromagnet with a coil. An armature, which can be coupled to the actuating element, can move between a first contact surface on the electromagnet and a second contact surface. An initial current or a higher holding current flows through the coil until a time at which the armature plate is reliably in contact with the contact surface of the electromagnet. An operating state of high-speed current reduction is then selected, wherein the opposite polarity of the supply voltage in comparison to the initial current flow is applied to the coil. A holding current then flows through the coil.

Abstract: An actuator has an actuating element and an actuating drive with an electromagnet with a coil. An armature, which can be coupled to the actuating element, can move between a first contact surface on the electromagnet and a second contact surface. An initial current or a higher holding current flows through the coil until a time at which the armature plate is reliably in contact with the contact surface of the electromagnet. An operating state of high-speed current reduction is then selected, wherein the opposite polarity of the supply voltage in comparison to the initial current flow is applied to the coil. A holding current then flows through the coil.

Abstract: The invention, intended for large power transformers and industrial heat transfer installations, is systemic in nature and calls upon two components which complement each other, the first one effecting the continuous on-line de-gassing of an insulating or heat transfer medium by the application of a vacuum whose pressure reducing effect is compensated by hydrostatic pressure or the combination of an impeller downstream and a restrictor upstream of the pressurized part; the second component of the complementary system is constituted by an expansion space which is separated from a displaceable buffer liquid by a membrane.

Abstract: By referencing either liquid volume or liquid pressure to liquid temperature, either in an implicit way and mechanically or in a non-implicit way and metronomically, the development of an electrical fault or loss of liquid can be detected. The present invention is based on the principle that any deviation from the relation between temperature and volume of a liquid, or, by implication, temperature and pressure in that liquid--the latter relation being applicable to closed systems only--is indicative either of an electrical fault in the transformer or of liquid loss from the transformer.