The Syracuse Cut-out.
This is a most ingenious device for opening a short circuit, depending on its action upon the sluggish movement of glycerine (Fig. 28).
A sealed glass tube pivoted near its centre contains a portion of glycerine sufficient to considerably overbalance it and keep one end down. A soft iron armature is attached to this tube in such manner that each time a current flows through a pair of electro-magnets, the attraction of the armature causes the tube to tilt and the glycerine flows along to the other end. Now it will be readily seen that if the tube is only tilted for a second or so, the slow-moving glycerine will not have flowed sufficiently to the end to overbalance it, but it requires an attraction of the armature for a considerable period. This electro-magnet is in circuit with the gas-lighting wires, the tube being provided with contacts in such manner that, when fully tilted, the circuit is broken. The momentary jerks imparted to the armature by the operation of a pendant or automatic burner will not be enough to permanently tilt the tube and break contact, but a short circuit will hold the armature tight down, until the increasing weight of glycerine causes the tube to open the circuit.
Fig. 28.
Fig. 29.