Bunnell Telegraph Repeaters

Bunnell Telegraph Repeaters

14A       Telegraph repeaters use different instruments to accomplish their purpose. The Weiny-Phillips repeater uses two transmitters and two special relays. Unlike a sounding repeater with its single contact arrangement, transmitters have double circuit contacts.

      The device shown here might be called a "sounding transmitter" since the basic instrument is a sounder with contacts added. On the base of the transmitter, below the sounder lever extension, is a switch. This is used to disable the repeater. With the switch in the "cut" position, each line into the repeater is terminated, and does not repeat into the other.

14B       The only difference between a standard relay and the Weiny-Phillips relay is the extra magnet over the usual magnets--but what a difference that is. The third magnet has two coils, diffrentially wound, and is encased in an iron shell which forms the return core of the electromagnet.

      In operation, as soon as the transmitter on the opposite side starts to operate, one of its contacts opens. This immediately opens the circuit to one side of the differential coil, thus holding the relay armature closed while its usual magnets are de-energized.

      One drawback to the Weiny-Phillips repeater was that it required four local batteries. However, it was a popular circuit, and improvements by Postal Telegraph and American Telephone kept the name, if not these instruments, alive for years.

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