A spring keeps the lever in the rest position with the circuit breaker open when no current is circulating through the electromagnet. It is clear that the relay is particularly suited for the transmission of messages in Morse code; indeed, in the second circuit, electricity circulates so long as a current is circulating through the electromagnet and if the electromagnet is connected to a telegraph line, the relay, in concomitance with a dash of a dispatch will transmit a dash to the receiver and in concomitance with a dot will transmit a dot. If, with the help of a relay on the spot, the problem caused by a weak signal in arrival could not be solved, it was necessary to divide the line into two or more trunks; also in this case it was necessary to use a relay that would automatically transmit dispatches from one intermediate station to the next and then to the receiver.
Hipp's relay differs from other relays in use at that time in that the lever with the mobile armature was equipped with a system of two spiral springs under different tensions pulling in different directions.
This setup, in which it is the difference in tension of the two springs that brings the armature into the rest position, greatly decreases the inertia of the vibrating rod, thus making its movements quicker.
The relay on display here has a square wooden base (14 x 14 cm), an overall height of 20 cm and is protected by a glass bell. ...continues