Dusty, can you pick a site and relay it to us?
You know how hard it is to track down everyone one-by-one to relay orders?
- Single-current Relay strument I and records Working.
The Siemens polarized relay, shown in fig.
20, which is the most modern pattern of relay used by the British Post Office, known as the " Post Office Standard Relay."
The coils of the electromagnets are differentially wound with silk-covered wire, 4 mils (= 004 inch) in diameter, to a total resistance of 400 ohms. This differential winding enables the instrument to be used for " duplex " working, but the connexions of the wires to the terminal screws are such that the relay can be used for ordinary single working.
The standard relay will work single current with a current of 3 milliamperes, though in practice about 10 would be used.
The relay tongue, being perfectly free to move, can be actuated by a comparatively weak current.
Normally a switch attached to the key cuts the battery off, and connects the line direct through the receiving relay; this switch is turned to " send " when transmission commences, and is moved back to " receive " when it ceases: this movement is done quite mechanically by the telegraphist, and as it is practically never forgotten, automatic devices (which have often been suggested) to effect the turning are wholly unnecessary.
To the line, thus hastening the discharge and the return of the relay tongue to its insulated stop.
Cut off, sets up an induced current of high tension, which causes a spark to jump across the contact points of the relay, and by oxidizing them makes it necessary for them to be frequently cleaned.
Incoming currents pass from line through one coil of the relay, the key, and either the battery or battery resistance, according as whether the key is raised or depressed.
The result is that the armature of the relay is attracted, and currents are sent through the sounder from the local battery, producing the signals from the distant station.
When the relay is operated it connects a bell between one of the wires of the circuit and earth, while the bell itself is arranged to respond to current pulsations in one direction only.
Among them were grooms leading the Tsar's beautiful relay horses covered with embroidered cloths.
At Kamenka a relay of horses was to wait which would take them to the Warsaw highroad, and from there they would hasten abroad with post horses.
This could not all be arranged that day, so on Evstafey's representation Pierre had to put off his departure till next day to allow time for the relay horses to be sent on in advance.