. Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems . LineSwitchboards g1 Ib 5/^/%7 toShelves Grd. 5/g. Secondary Line Switchboard2nd3oard 1st. Board. Otherboards \5upy0rd. [b B in Any /2/5C 5> To Supy 5i0. ran 0 U<i Dash Pot Relay 2^jM man 3/iow rU Buzzer Key ( / IF □ Fig. 289.—Release signal supervision, tell-tale and alarm scheme. 362 AUTOMATIC TELEPHONY relay has not time to act. If for any cause the release magnet of a selec-tor draws current longer than it should, the dash-pot relay has time toclose its contacts. This lights th
. Automatic telephony; a comprehensive treatise on automatic and semi-automatic systems . LineSwitchboards g1 Ib 5/^/%7 toShelves Grd. 5/g. Secondary Line Switchboard2nd3oard 1st. Board. Otherboards \5upy0rd. [b B in Any /2/5C 5> To Supy 5i0. ran 0 U<i Dash Pot Relay 2^jM man 3/iow rU Buzzer Key ( / IF □ Fig. 289.—Release signal supervision, tell-tale and alarm scheme. 362 AUTOMATIC TELEPHONY relay has not time to act. If for any cause the release magnet of a selec-tor draws current longer than it should, the dash-pot relay has time toclose its contacts. This lights the tell-tale lamp and shunts the 1300-ohmrelay with a 15-ohm relay. This permits the 15-ohm relay on the boardto pull up, lighting the pilot lamp. The tell-tale lamp current operatesthe alarm relay which causes the buzzer to sound. The secondand third selectors are grouped in a similar way. The lineswitch boards are also grouped for this purpose. The super-visory apparatus for a group is placed on the supervisory panel of thepower board and a single wire run to the group of boards. There is onerelease pilot lamp on a board and no shelf pilot, for all the connectorsare treated as
Size: 1571px × 1591px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjecttelephone, bookyear19
