Abstract: The seam welding machine with welding arrangement 10 has a lower part (1) and an upper (2). Load-bearing components are upper and lower longitudinal girders (20, 21) with a rigid connection (3, 4) between them. For clamping sheet blanks (7, 8) for welding, two clamping blocks are provided, each with upper and lower pressure beams (24, 25); at least the upper pressure beams (24) can be raised and lowered by means of jacks. For longitudinal transport of workpieces (7, 8) along the weld axis (Z), each beam has a feed unit (40, 41). Each feed unit comprises a longitudinal guide extending in the direction of the axis (Z), a slide, with clamping devices, guided on this longitudinal guide, and a reversible linear drive connected to the slide.

Abstract: The high-voltage switch with a closing resistor has a main switch point and, parallel to this, an auxiliary switch point, the closing resistor (19) being in series with the auxiliary switch point. A movable contact (17) of the auxiliary switch point is driven via a thrust-crank drive (16), in such a way that it closes before the main switch point and opens again after the main switch point has closed.In this high-voltage switch, the object is to achieve a cycle of movement which, while ensuring a saving of components of the drive, can be adapted in a simple way to differing network conditions.This is achieved because the thrust-crank drive (16) has a compressible joint (23), and because the movable contact (17) is coupled to two impact rings (34, 35) which interact with two stops (36, 37).

Abstract: Two series-connected main switching contacts (1a, 1b) mounted on a housing (7) are actuated, in conjunction with an auxiliary switching unit (4) for switching a closing or starting resistance (3), by a drive (5) via a switching drive mechanism (6). To obviate the need for a second auxiliary switching unit and to achieve other cost reductions, the closing resistance (3) and the auxiliary switching unit (4) are connected in a parallel circuit and in series between the main switching contacts (1a, 1b). The foregoing components are accommodated in the housing (7). During a switching-on process, the auxiliary switching unit (4) closes after the main switching contacts close (1a, 1b) and the closing resistance (3) is bypassed. During the switching-off process, the auxiliary switching unit opens after the main switching contacts (1a, 1b).

Abstract: Between a fixed contact member (2) having a rated-current contact and a fixed arcing contact (3) which acts in conjunction with a moving contact member (4) having a moving rated-current contact (5) and moving arcing contact (6), and a first flange (7) an insertion resistance (8) is arranged.In order to save a further pair of contacts, the rated-current contact of the fixed contact member (2) is constructed as a sliding rated-current contact (14) which can be displaced in the switching-on direction by the moving contact member (4). During the switching-on process, it is first contacted by the moving rated-current contact (5) which creates a current path including a resistance contact (9) and the insertion resistance (8). A little later, the insertion resistance (8) is bridged when the moving arcing contact (6) comes into contact with the fixed arcing contact (3), which is connected to the first flange (7) by means of a conductor (20).

Abstract: An electrical high-tension circuit breaker with main contacts and auxiliary contacts in parallel to the main contacts. Both sets of contacts are actuated by hydraulic drives which are fed from a hydraulic accumulator. The drive of this circuit breaker is of high reliability and small size considering the power to be switched. This is achieved with a main drive which contains a piston-cylinder arrangement which can be pressurized with hydraulic fluid via a main valve and a secondary drive which is actuated via a valve arrangement. The valve arrangement is controllable as a function of the position of the main contacts and/or the auxiliary contacts. With this drive, failure-susceptible elements, such as catches, mechanical dampers and couplings, are avoided. The drive is preferably for high-tension circuit breakers for voltages above 220 kV.

Abstract: A hydraulic drive for an electrical switch is disclosed including magnetically operated control signal organs for initiating closing and opening of the electrical switch which is hydraulically driven by a drive with a differential piston moving in a drive cylinder. A switch-over control valve is employed for selectively pressurizing and depressurizing a larger end face of the piston. In order to prevent "pumping" of the switch by such a switch drive system according to the present invention, the control signal organ which is opened in connection with the initiation of the closing of the switch is manipulated hydraulically at approximately the same time as the pressurization by the switch-over control valve of the larger piston end face of the differential piston of the drive commences. The hydraulic manipulation shifts the control signal organ back into a closed position. This arrangement permits at most only one on-off switching cycle to occur, and thus "pumping" of the switch is prevented.

Abstract: A method and apparatus to monitor a compressible gas volume of one or more hydropneumatic storage tanks of an energy-storing system includes at least one pump to fill the individual storage tanks with hydraulic fluid. The fluid is isolated from the gas volume in each storage tank or unit by a movable partition. The gas volumes of the storage tanks are monitored continuously and free of error for the early detection and signaling of gas volume losses by the use of a minimum of maintenance-free devices. The monitoring is accomplished by determining the state of flow of the hydraulic fluid entering the several hydropneumatic storage tanks while the pump is running. In the event of a coincidence of a running pump and an interruption of the flow to a tank, a loss of gas volume is indicated. A flow monitor having a control contact within each pipeline supplying the hydraulic fluid as well as a signal device for indicating the pump operation is provided.

Abstract: An electrical switch is provided with at least one set of stationary and movable main contacts for opening and closing the circuit controlled by it, and a set of stationary and movable auxiliary contacts for connecting a resistor in parallel with the main contacts and hence into the circuit controlled by the switch during a switching-in operation prior to engagement of the main contacts. The resistor is then disconnected either after the main contacts have engaged, or it is disconnected later during a switching-out operation prior to dis-engagement of the main contacts. Both operational modes are effected by means of a follower device which couples the movable auxiliary contact with the movable main contact.