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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Page 78<br />
PART 10<br />
ADJUSTMENT AND MAINTENANCE DATA<br />
FOR No. 4150 TYPE SELECTORS<br />
General<br />
1. The following pages cover the tests and adjustments for the 4150 type<br />
selector mounted on its appropriate bank. (In the case of selectors obtained without<br />
banks the requirements under sections 8, 9, 10 and 11 and electrical requirements<br />
must be met by adjustment after assembly on its bank).<br />
2. The test figures are provided for checking the condition of selectors and are<br />
the maximum tolerances and are only allowed for testing purposes. When readjustments<br />
are being made the readjust figures shall apply.<br />
Preliminary<br />
1. The wiper assembly shall be secure on the hub, it shall rotate freely and<br />
have slight side play but not greater than 15 mil.<br />
2. The brush assembly shall be securely fixed to the bank frame. (The feeder<br />
brushes must be free from any distortion).<br />
3. The armature assembly shall be seated with both grooves on the knife edge<br />
and shall be clear of all other parts of the frame.<br />
4. The pawl spring and clamp plate shall be clear of the pawl stop when the<br />
armature is fully operated.<br />
5. The armature restoring spring adjusting screws shall not bind in the springs,<br />
and shall not be so loose as to allow the turns of the springs to slip over the<br />
threads.<br />
Adjustments<br />
1. All adjustments shall apply to the selector mounted vertically on its associated<br />
bank with the magnet assembly uppermost.<br />
2. Armature Knife Edge.<br />
2.1 The armature knife edge shall be adjusted so that the pawl tip overlaps the<br />
ratchet wheel on both sides, and that when viewed from the side the<br />
armature strikes the core within a in. of the centre of the core, judged by<br />
eye.<br />
2.2 Check that when the armature is fully operated by hand, the armature<br />
assembly clears the coil box by 10 mil in all directions.