GB380594A - An improved selective electric switch - Google Patents

Abstract

380,594. Supply systems. LANDIS ET GYR SOC. ANON., 1, Hofstrasse, Zug, Switzerland. Sept. 16, 1931, No. 25931. Convention date, Sept. 20, 1930. [Class 38 (iv).] Selecting sources in service.-Comprises an automatic switching arrangement for selecting a preferred energized line from a number of supply lines and connecting it to an auxiliary circuit. If the supply in that line fails the switch automatically hunts round to find another energized line but returns to the preferred line as soon as it becomes re-energized. The switch consists of a drum 9, carrying a number of cams 10 which, in different positions of the drum, close switches to effect connection between an auxiliary line V and one of the supply lines I, II, &c. Relays P, II<11>, &c., connected to the supply lines, engage with a lever 27 bv means of lever 34 and when one or more of the lines are energized the lever 27 is moved to the position shown, with its lower end out of the path of a rotatable detent device 7 connected to a clockwork motor used to rotate the switch drum. A relay 15 connected to the auxiliary line V engages with a lever 18 and when energized by the switch connecting the auxiliary line ot an energized supply moves the lever so that the part 19 moves into the path of the detent 7 and stops the motor rotating the switch. In order, however, to prevent the switch being stopped in an intermediate position, a lever 22 has an arm 23 that engages the pin 21 'on the lever 18 and holds the part 19 out of the path of the detent 7 until the pawl 25 drops into the tooth of the ratchet 26. If all the supplies are de-energized the lever 27 will be moved by spring 29 into the path of the detent 7 in order to prevent the spring motor running down. This motor is maintained wound by a Ferraris motor 3. Lever 27 has a pin 30 that engages lever 22 to prevent motor being stopped before a switching operation is completed. In order to obtain preferential selection of a particular supply a relay VII is connected to that source (as shown II) and operates contacts 38 connected in the circuit of the relay 15, and the switch is provided with an additional pair of contacts connected in parallel with the contacts 38 and closed by a cam at the same time as the preferred course II is connected to the auxiliary line V. When supply II is energized, the contacts 38. are open, and the circuit of relay 15 is completed by the additional contacts on the switch, When the supply II fails, the contacts 38 close and complete the circuit of the relay 15, but since it is de-energized it allows the switch to hunt around to find an energized source and effect connection of the auxiliary to that. As soon, however, as the supply II becomes again energized, the circuit of relay 15 is broken by the contacts 38 opening, and the switch resets itself to connect line V to the supply II, in which position the circuit of relay 15 is completed by the contacts on switch.