TRAFFIC CONTROL TELEPHONE SYSTEMS Circuit - Sam Hallas
TRAFFIC CONTROL TELEPHONE SYSTEMS Circuit - Sam Hallas
TRAFFIC CONTROL TELEPHONE SYSTEMS Circuit - Sam Hallas
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(b) The contact spring (Z) in the normal position shall press against the code<br />
wheel (E) with a pressure of ? gramme minimum to 1 gramme maximum.<br />
(c) The contact spring (Z) when one step before or beyond the ringing terminals<br />
shall not make contact with them.<br />
Spiral Spring<br />
(a) When the selector is mounted in a horizontal or in a vertical position with<br />
the armature (O) at the bottom, the tension of the spiral spring (AB) shall be<br />
sufficient to restore the code wheel (E), either to the normal or to the time<br />
receiving position, whenever the rocker arm (S) comes into its normal position<br />
during the operation of the selector and the code wheel is not in such a<br />
position that it will be held by the holding spring (K) engaging with the code<br />
pins (E) or time arm lug. For this test the contact spring on the code wheel<br />
shall be advanced by operating the armature by hand:-<br />
1. One step beyond the normal position.<br />
2. One step beyond each ringing terminal.<br />
3. One step beyond the time ringing terminal. In each case the armature shall<br />
be released slowly.<br />
Retractile Spring on Rocker Arm<br />
(a) The tension of the retractile spring (R) on the rocker arm (S) including the<br />
tension of the holding spring shall be sufficient to restore the rocker arm to<br />
normal at all times when no current is flowing through the selector and also to<br />
meet the tests specified in the electrical requirements.<br />
Armature and Magnet Cores<br />
(a) The centre line of the magnet (AJ) shall be equally distant from the cores<br />
(AK) within 0.02 inch either side.<br />
(b) The armature lever shall clear all adjacent parts except the rocker arm (S)<br />
throughout its entire stroke. The allowable vertical or horizontal play shall<br />
not permit the lever to touch such parts.<br />
(c) The end play of the armature shaft, the ratchet wheel shaft, the rocker wheel<br />
shaft and the holding pawl, shall not be greater than 0.01 inch,<br />
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