TRAFFIC CONTROL TELEPHONE SYSTEMS Circuit - Sam Hallas

More documents

Recommendations

Info

Page 18 4001-A Selector Key, Coded 3-11-3 Fig. 7.
The keys are easily removed from the key case by simply turning the mounting screw U counter-clockwise for a quarter turn. This causes the spring latch B to disengage from the framework bars. The spring latch B, in addition to securing the key, completes the K3 connection through the key case framework to the external K3 terminal. The keys, when mounted, make contact with springs in the back of the case, and these springs are connected with the external terminals K1 and K2. Connections are therefore automatically accomplished when a key is mounted in its key case making the changing of a key a very simple matter. General Requirements and Description The speed of the key is regulated by a governor Q which can be adjusted by bending the springs carrying the weights, inwards or outwards, to increase or decrease respectively the speed of the key. The springs should be so adjusted that the impulse wheel makes one complete revolution in 7½ to 8 seconds. Fig. 7 illustrates how a key is coded, and will be referred to in the following description. When the key is normal, the end of the inner spring J1 should clear the impulse wheel K3, as shown at A in Fig. 7, and when the wheel is revolving, should make contact with it for the duration of the revolution. It is this contact between K1 and K3 which operates the battery relay of the system, thus applying battery to the line. K1 and K2 should be closed only when K1 passes over a tooth of the impulse wheel, or when passing over a flat coding segment, and should be open when K1 drops into a hollow between teeth, or is passing over a bent-up segment. These makes and breaks of K1 and K2 are reproduced by the battery reversing relay of the system, thus sending reversed impulses to line. Impulse Ratio The springs K1 and K2 should be so adjusted that the time the contacts are closed when passing over the teeth of the impulsing wheel equals the time they are open. The impulse ratio, or comparison of the closed and open periods, of K1 and K2 can be determined with the use of a damped voltmeter and battery or a milli-ammeter, battery and non-inductive resistor in series with KI and K2. The coding segments should be adjusted so that an uninterrupted train of impulses, such as General Call (see General Call, page 22) are transmitted, then the average reading of the meter, during the impulsing period, should be one half of the steady reading of the meter when the contacts K1, K2 are closed or shorted. (See also Mechanical Requirements page 23 paragraph 6.) Method of Coding the Key When the impulse wheel is rotating each closure of KI, K2 is one impulse, and each opening of the contacts is another impulse. The code consists of three digits, the sum of which, for any code is always 17 impulses. The inter-digital pauses in impulsing are obtained by the use of two segments, of which there are two types. Page 19
Page 2 and 3: TRAFFIC CONTROL TELEPHONE SYSTEMS C
Page 4 and 5: CONTENTS Part Title Page 1 Key Syst
Page 6 and 7: swing of the meter needle either si
Page 8 and 9: One No. 4002-B Selector Key Case (c
Page 11 and 12: wires. This change of polarity is t
Page 13 and 14: Case), K2 terminal (Time Sending Se
Page 15 and 16: Where satisfactory operation cannot
Page 17 and 18: one is available (if not, with an o
Page 19: PART 2 4001-A SELECTOR KEY Selector
Page 23 and 24: Letter. Name. S.T.C. Code. A Impuls
Page 25 and 26: 4. When the key is normal the tip o
Page 27 and 28: the time terminal. During selective
Page 29 and 30: Cycle of Events on Receiving a Code
Page 31 and 32: Mechanical Requirements To assist i
Page 33 and 34: (b) The contact spring (Z) in the n
Page 35 and 36: Letter Name 4301-A 4304-A 4305-B A
Page 37 and 38: General PART 4 4001-B SELECTOR TEST
Page 39 and 40: 4001-B Selector Test Set, Schematic
Page 41 and 42: General PART 5 DIAL SYSTEM, SELECTI
Page 43 and 44: The speak key also connects the con
Page 45 and 46: normal, Relay IR is held operated a
Page 47 and 48: here that from SC bank contacts 29
Page 49 and 50: from Line switch SC banks 1 and 2 a
Page 51 and 52: Line Test Set . . . . . . Designed
Page 53 and 54: Line Voltage Curves Fig. 14. The op
Page 55 and 56: General PART 7 LINE TEST SET-LU.310
Page 57 and 58: Operating Instructions 1. Voltage M
Page 59 and 60: the particular line to the earthed
Page 61 and 62: Operate CVK, note meter reading on
Page 63 and 64: 10. Impulse Ratio Check on Selectiv
Page 65 and 66: 12. Telephone Communication. (See F
Page 67 and 68: Page 65
Page 69 and 70: Armature Travel Armature travel is
Page 71 and 72:
Contact Sequence The standard conta
Page 73 and 74:
chloride or trichlorethylene. The t
Page 75 and 76:
PART 9 ADJUSTMENT AND MAINTENANCE D
Page 77 and 78:
9. Armature Restoring Springs:— T
Page 79 and 80:
Oil dag should be applied as above
Page 81 and 82:
3. Pawl Spring Tension 3.1 With the
Page 83 and 84:
8.6 The wipers shall exert a pressu
Page 85 and 86:
2.2 The wipers shall rotate smoothl
Page 87:
Registered Office: CONNAUGHT HOUSE
show all

TRAFFIC CONTROL TELEPHONE SYSTEMS Circuit - Sam Hallas

Create successful ePaper yourself

Delete template?

Save as template?