GB1438980A - Electrical connecting and disconnecting device - Google Patents

Abstract

1438980 Heavy current switches SIEMENS AG 25 June 1973 [23 June 1972] 30148/73 Heading H1N An electrical switching device for applying and removing a heavy current short circuit connection and suitable for use under conditions of residual excitation of polyphase electrical machine is shown in single-pole form in Fig. 1 and includes a displaceable first member 3, with drive means not shown or described and which is electrically and slidably connected to a bar 1 by a cage 2 and a second member 6 displaceable with the first into a contact making position with a fixed conductor 10 which is provided with counter-contacts 4 and 11. The first member 3 is hollow and switching means 5 is provided within it comprising a conventional vacuum switch, Fig. 2, consisting of a relatively fixed contact 13 connected to the second member 6, a relatively movable contact 14 which is connected to the first member 3 at all times, and including electromagnetic means 7, 18 for opening the contacts of the switching means against the closing force of springs 19, 20. Control means for the switching means 5 and operable in dependence on the displacement movement of the first member 3 comprises switches 9 and 21 actuated by an abutment 8 on member 3 and a relay 22 (Fig. 3a, not shown). In operation, as the first and second members 3, 6 are displaced from an "off" position (Fig. 3a) in which contacts 13, 14 of the switching means 5 are closed and the members 3, 6 are disconnected from the counter-contacts 4, 11 of the conductor 10, towards the contact making position of the device the control means first causes the contacts 13, 14 of the switching means 5 to open (Fig. 3b) before the second member 6 engages the counter-contact 11 (Fig. 3c) but immediately following this engagement the contacts 13, 14 are caused to close (Fig. 3d) and in the fully displaced position the first member 3 engages the counter-contact 4 in the fully connected position of the device. For disconnecting the reverse sequence applies. An alternative arrangement in which the drive means for the displacement action is arranged to act on the bar 1 and thus displace the bar 1, cage 2, and member 3 jointly is referred to.