Strowger selector operation diagrams – contents
1
Ordinary final selector - idle state 2
Final selector - moment of seizure 3
Final selector - just after seizure 4
Final selector - vertical stepping 5
Final selector - end of vertical stepping 6
Final selector - switch over to rotary 7
Final selector - rotary stepping 8
Final selector - end of rotary steps 9
Subscriber’s uniselector with double homing arc 10
Final selector - called line is free 11
Final selector - ringing a free line 12
Final selector - call answered 13
Caller’s uniselector - lifting the handset 14
Caller’s uniselector - hunting for free group selector 15
Caller’s uniselector - free group selector found 16
Caller’s uniselector - call established 17
Caller’s uniselector - call terminates 18
Subscriber’s uniselector with single homing arc 19
Uniselector - incoming call 20
Uniselector - P guarding during ringing 21
Uniselector - caller lifts handset 22
Uniselector - free 1st selector found 23
Uniselector - connected 24
Uniselector - end of call 25
UAX13 group selector - idle state 26
UAX13 group selector - moment of seizure 27
UAX13 group selector - preparing for dial pulses 28
UAX13 group selector - end of vertical stepping 29
UAX13 group selector - free next selector found 30
UAX13 group selector - connecting to next selector 31
Ordinary group selector 200 outlet 32
Ordinary group selector - moment of seizure 33
Ordinary group selector - vertical stepping 34
Ordinary group selector - end of vertical stepping 35
Ordinary group selector - first rotary step 36
Ordinary group selector - free outlet found 37
Ordinary group selector - connecting 38
Ordinary group selector - normal release 39
UAX13 group selector and ordinary final selector 40
When group and final selector are both UAX13 41
UAX13 group selector - moment of connection 42
UAX13 group selector - providing 150 Ohm battery 43
UAX13 group selector - external relay activation 44
UAX13 group selector - connection made 45
200A
_
+
CD2200
N3
P wire
B2
A1
1300
B4
MR2
R2
200
B
CD1
5 700
B1
R3
1k2
E3
CD
N2
NR2
F6
1500E
E5
CD4
E1//D1
NR1
VM
H5
RM
Ordinary final selector – idle state
METER PULSE
CONNECTION
HERE
ROTARY
RELEASE
CONNECTION
TO F, H AND
J RELAYS
2
200A
_
+
CD2200
N3
P
B2
A1
1300
B4
MR2
R2
B
CD1
5 700
B1
R3
E3
CD
N2
NR2
F6
E
E5
CD4
E1
NR1
VM
H5
RM
Final selector – moment of seizure – A operates and removes short-circuit of B
3
1500
CURRENT FLOW
IN RED
200A
_
+CD2 200
N3
P
B2
A1
1300
B4
MR2
R2
B
CD1
5 700
B1
R3
E3
CD
N2
NR2
F6
1500E
E5
CD4
E1
NR1
VM
H5
RM
Final selector – just after seizure – A, B and CD operate
INCOMING
PRIVATE WIRE
EARTHED
4
200A
_
+CD2 200
N3
P
B2
A1
1300
B4
MR2
R2
B
CD1
5 700
B1
R3
1k2
E3
CD
N2
NR2
F6
1500E
E5
CD4
E1
NR1
VM
H5
RM
Final selector – vertical stepping – A and VM are pulsing, B and CD are holding on short circuits
short-
circuit
5
200A
_
+CD2 200
N3
P
B2
A1
1300
B4
MR2
R2
B
CD1
5 700
B1
R3
E3
CD
N2
NR2
F6
1500E
E5
CD4
E1
NR1
VM
H5
RM
Final selector – end of vertical stepping – A and B operate, CD releases, E slow to operate
6
200A
_
+CD2 200
N3
P
B2
A1
1300
B4
MR2
R2
B
CD1
5 700
B1
R3
E3
CD
N2
NR2
F6
1500E
E5
CD4
E1
NR1
VM
H5
RM
Final selector – switch over to rotary – A, B and E operate, CD re-operates
short-circuit on
CD removed
7
200A
_
+CD2 200
N3
P
B21300
B4
MR2
R2
B
CD1
5 700
B1
R3
1k2
E3
CD
N2
NR2
F6
1500E
E5
CD4
E1
NR1
VM
H5
RM
Final selector – rotary stepping – A and RM pulsing, B and CD holding, E operates
A1
8
200A
_
+CD2 200
N3
P
B21300
B4
MR2
R2
B
CD1
5 700
B1
R3
E3
CD
N2
NR2
F6
1500E
E5
CD4
E1
NR1
VM
H5
RM
Final selector – end of rotary steps – A and B operate, CD and E release slowly, CD re-operates
A1
9
_
+
700
DMdm
DM
Subscriber’s uniselector with DOUBLE homing arc – idle state
L
1300K
L2
K3
K5
L1x
H
K1
K2
P
H4
H3
+
_
M.D.F.LINE SIDE EXCH SIDE
M.D.F.
MULT. LOCALB3
CD3
H
P
FINAL SELECTOR
SUBSCRIBER’S UNISELECTOR
-50V
10
_
+
700
DMdm
DM
Final selector – called line is free – CD releases, H (900 Ohm) and K operate, L is disconnected
L
1300K
L2
K3
K5
L1x
H
K1
K2
P
H4
H3
+
_
M.D.F.LINE SIDE EXCH SIDE
M.D.F.
MULT. LOCALB3
CD3
H
P
FINAL SELECTOR
(after last digit dialled)
CALLED SUBSCRIBER’S UNISELECTOR
900
PREPARED FOR RINGING
IF NOT ENGAGEDCALLED
PHONE11
Ringing current in green
Final selector – ringing a free line – E releases slowly, CD, J and H (on 400 Ohm winding) operate
300
D
J3
RING TONE
TO CALLER
E4
F5
+
P
_
R1
400F
H400 900
H3
H4
F7
F8
F1F2
H1
B4
F4x
B3
CD3
H2
570 200A 200
N2
J800
J1
INT RING
TO CALLED
BELL
VM
D1
E
CD4
RING RTN
BATTERYHOLDING
UNISELECTOR
K RELAY
1500
12
Final selector – call answered – CD, D, E and F operate, J releases (slowly) after meter pulse
300
D
J3
+
P
_
R1
400F
H400 900
H3
H4
F7
F8
F1F2
H1
B4
F4x
B3
H2
570 200A 200
N2
J800
J1
INT RING
E
VM
CD4
D1
VOICE CONNECTION
HOLDING
UNISELECTOR
K RELAY
CD3
RING TONE
TO CALLER
F5
E4
1500
13
DMdmDM
Caller’s uniselector – lifting the handset – L operates slowly
1300K
L2
K3
K5
L1x
H
P
M.D.F.
MULT. LOCAL
B3
CD3
H
P
_
+
700
K1
K2
H4
H3
+
_
L
CALLER
LINE SIDE EXCH SIDE
CALLER’S UNISELECTORMULTIPLE FINAL SELECTORS
TO GROUP
SELECTORS
GUARDED
GROUP
SELECTORS
14
DMdmDM
Caller’s uniselector – hunting for free group selector - L operates, DM pulsing
1300K
L2
K3
K5
L1x
HP
M.D.F.
MULT. LOCAL
B3
CD3
H
P
_
+
700
K1
K2
H4
H3
+
_
L
CALLER
LINE SIDE EXCH SIDE
CALLER’S UNISELECTORMULTIPLE FINAL SELECTORS
P WIRE
MULTIPLE
EARTHED
VIA HOMING
ARC HOME
POSITION
TO GROUP
SELECTORS
GUARDED
GROUP
SELECTORS
15
DMdmDM
Caller’s uniselector – free group selector found – K operates, L releases slowly
1300K
L2
K3
K5
L1x
H
P
M.D.F.
MULT. LOCAL
B3
CD3
H
P
_
+
700
K1
K2
H4
H3
+
_
L
CALLER
LINE SIDE EXCH SIDE
CALLER’S UNISELECTORMULTIPLE FINAL SELECTORS
P WIRE
MULTIPLE
EARTHED
VIA HOMING
ARC
GUARDED
GROUP
SELECTORS
LOOP CURRENT
FROM GROUP
SELECTOR
L2 AND K3 PROVIDE
TEMPORARY EARTH
TO SEIZED SELECTOR
16
DMdmDM
Caller’s uniselector – call established – K held by group selector P wire
1300K
L2
K3
K5
L1x
H
P
M.D.F.
MULT. LOCAL
B3
CD3
H
P
_
+
700
K1
K2
H4
H3
+
_
L
CALLER
LINE SIDE EXCH SIDE
CALLER’S UNISELECTORMULTIPLE FINAL SELECTORS
P WIRE
MULTIPLE
EARTHED
VIA HOMING
ARC
LOOP CURRENT
FROM GROUP
SELECTOR
SEIZED SELECTOR
RETURNS EARTH
17
DMdmDM
Caller’s uniselector - call terminates - no loop current – K releases – DM steps home
1300K
L2
K3
K5
L1x
H
P
M.D.F.
MULT. LOCAL
B3
CD3
H
P
_
+
700
K1
K2
H4
H3
+
_
L
CALLER
LINE SIDE EXCH SIDE
CALLER’S UNISELECTORMULTIPLE FINAL SELECTORS
P WIRE
MULTIPLE
EARTHED
VIA HOMING
ARC
18
_
+
700
DMdm
DM
Subscriber’s uniselector with SINGLE homing arc - idle state - H, K and L not operating
L
1300K
L2
K3
K5
L1
H
K1
K2
P
H4
H3
+
_
M.D.F.LINE SIDE EXCH SIDE
M.D.F.
MULT. LOCALB3
CD3
H
P
FINAL SELECTOR
SUBSCRIBER’S UNISELECTOR
900
400
BELL
LOOP
- 50V
19
_
+
700
Uniselector – incoming call – H (900) operates on brief CD release, K operates, L releases
L
K1
K2H4
H3
+
_
M.D.F.LINE SIDE EXCH SIDE
M.D.F.
MULT. LOCALB3
CD3
H
P
FINAL SELECTOR
(last digit dialled)
CALLED SUBSCRIBER’S UNISELECTOR
900
PREPARED FOR RINGING
IF NOT ENGAGED
DMdm
DM
1300K
K3
K5
L1
H
P
L2
BELL
LOOP20
_
+
700
Uniselector– P guarding during ringing – CD operates again, H(400) takes over from H(900)
L
K1
K2H4
H3
+
_
M.D.F.LINE SIDE EXCH SIDE
M.D.F.
MULT. LOCALB3
CD3
H
P
FINAL SELECTOR
CALLED SUBSCRIBER’S UNISELECTOR
900
PREPARED FOR RINGING
IF NOT ENGAGED
DMdm
DM
1300K
K3
K5
L1
H
P
L2
BELL
LOOP
H2
400
21
_
+
700
DMdm
DM
Uniselector – caller lifts handset – L operates on caller loop, DM steps on DMdm
L
1300K
L2
K3
K5
L1
H
K1
K2
P
H4
H3
+
_
M.D.F.LINE SIDE EXCH SIDE
M.D.F.
MULT. LOCALB3
CD3
H
P
FINAL SELECTOR
CALLING SUBSCRIBER’S UNISELECTOR
900
400
CALLER
LOOP22
_
+
700
DMdm
DM
Uniselector – free 1st selector found – K operates, L releases slowly
L
1300K
L2
K3
K5
L1
H
K1
K2
P
H4
H3
+
_
M.D.F.LINE SIDE EXCH SIDE
M.D.F.
MULT. LOCALB3
CD3
H
P
FINAL SELECTOR
CALLING SUBSCRIBER’S UNISELECTOR
900
400
CALLER
LOOP
FREE 1st
SELECTOR
1st
SELECTOR
LOOP
23
_
+
700
DMdm
DM
Uniselector – connected – K operates on 1st selector earth
L
1300K
L2
K3
K5
L1
H
K1
K2
P
H4
H3
+
_
M.D.F.LINE SIDE EXCH SIDE
M.D.F.
MULT. LOCALB3
CD3
H
P
FINAL SELECTOR
CALLING SUBSCRIBER’S UNISELECTOR
900
400
CALLER
LOOP
FREE 1st
SELECTOR
EARTH
RETURNED
1st
SELECTOR
LOOP
24
_
+
700
DMdm
DM
Uniselector – end of call – P earth removed, K releases, DM steps home
L
1300K
L2
K3
K5
L1
H
K1
K2
P
H4
H3
+
_
M.D.F.LINE SIDE EXCH SIDE
M.D.F.
MULT. LOCALB3
CD3
H
P
FINAL SELECTOR
CALLING SUBSCRIBER’S UNISELECTOR
900
400
OPEN
LOOP
FREE 1st
SELECTOR
EARTH
REMOVED
25
200A
_
+
200
P
B1
2000 2000
2000
YC
2k
C
1300B
VMRM
UAX13 group selector – idle state
RELEASE
RELAY
_
+
M
P
570M
3 1000
11
1000
MRA
VMB
CBO
CB
NR1
H
N3
S1
TM1
B2B5
C3
H2HX1
CC4
H4
R1
N1
200
QA
N2
CC
HX
B3
H3 B4
CC3
TM2
TM
YA
150 YB
500
CC2
H1
C2
CC1
H5H6
S2
S3CC5
H7
TP
HOLD
TP
STARTRELEASE
ALARM
EARTH
TP RELEASE
DIAL TONE EARTH
N.U. TONE EARTH
BUSY TONE EARTH
INT BATT & EARTH
A1
C1
(AT BATT LEVEL)
26
200A
_
+
200
P
B1
2000 2000
2000
YC
2k
C
1300B
VMRM
UAX13 group selector – moment of seizure – A and B operate
RELEASE
RELAY
_
+
M
P
570M
3 1000
11
1000
MRA
VMB
CBO
CB
NR1
H
N3
S1
TM1
B2B5
C3
H2HX1
CC4
H4
R1
N1
200
QA
N2
CC
HX
B3
H3 B4
CC3
TM2
TM
YA
150 YB
500
CC2
H1
C2
CC1
H5H6
S2
S3CC5
H7
TP
HOLD
TP
STARTRELEASE
ALARM
EARTH
TP RELEASE
DIAL TONE EARTH
N.U. TONE EARTH
BUSY TONE EARTH
INT BATT & EARTH
A1
C1
(AT EARTH LEVEL)
27
200A
_
+
200
P
B1
2000 2000
2000
YC
2k
C
1300B
VMRM
UAX13 group selector – preparing for dial pulses – C and CC operate
RELEASE
RELAY
_
+
M
P
570M
3 1000
11
1000
MRA
VMB
CBO
CB
NR1
H
N3
S1
TM1
B2B5
C3
H2HX1
CC4
H4
R1
N1
200
QA
N2
CC
HX
B3
H3 B4
CC3
TM2
TM
YA
150 YB
500
CC2
H1
C2
CC1
H5H6
S2
S3CC5
H7
TP
HOLD
TP
STARTRELEASE
ALARM
EARTH
TP RELEASE
DIAL TONE EARTH
N.U. TONE EARTH
BUSY TONE EARTH
INT BATT & EARTH
A1
C1
28
200A
_
+
200
P
B1
2000 2000
2000
YC
2k
C
1300B
VMRM
UAX13 group selector – end of vertical stepping – C, CC release, hunting for free outlet
RELEASE
RELAY
_
+
M
P
570M
3 1000
11
1000
MRA
VMB
CBO
CB
NR1
H
N3
S1
TM1
B2B5
C3
H2HX1
CC4
H4
R1
N1
200
QA
N2
CC
HX
B3
H3 B4
CC3
TM2
TM
YA
150 YB
500
CC2
H1
C2
CC1
H5H6
S2
S3CC5
H7
TP
HOLD
TP
STARTRELEASE
ALARM
EARTH
TP RELEASE
DIAL TONE EARTH
N.U. TONE EARTH
BUSY TONE EARTH
INT BATT & EARTH
A1
C1
E.G. DIALLED 6
E.G. NR 3 IS FREE
29
200A
_
+
200
P
B1
2000 2000
2000
YC
2k
C
1300B
VMRM
UAX13 group selector – free next selector found – HX operates on P wire battery(!)
RELEASE
RELAY
_
+
M
P
570M
3 1000
11
1000
MRA
VMB
CBO
CB
NR1
H
N3
S1
TM1
B2B5
C3
H2HX1
CC4
H4
R1
N1
200
QA
N2
CC
HX
B3
H3 B4
CC3
TM2
TM
YA
150 YB
500
CC2
H1
C2
CC1
H5H6
S2
S3CC5
H7
TP
HOLD
TP
STARTRELEASE
ALARM
EARTH
TP RELEASE
DIAL TONE EARTH
N.U. TONE EARTH
BUSY TONE EARTH
INT BATT & EARTH
A1
C1
E.G. DIALLED 6
E.G. NR 3 IS FREE
P wire
on batt !!
30
200A
_
+
200
P
B1
2000 2000
2000
YC
2k
C
1300B
VMRM
UAX13 group selector – connecting to next selector – H operates, HX, A and B release
RELEASE
RELAY
_
+
M
P
570M
3 1000
11
1000
MRA
VMB
CBO
CB
NR1
H
N3
S1
TM1
B2B5
C3
H2HX1
CC4
H4
R1
N1
200
QA
N2
CC
HX
B3
H3 B4
CC3
TM2
TM
YA
150 YB
500
CC2
H1
C2
CC1
H5H6
S2
S3CC5
H7
TP
HOLD
TP
STARTRELEASE
ALARM
EARTH
TP RELEASE
DIAL TONE EARTH
N.U. TONE EARTH
BUSY TONE EARTH
INT BATT & EARTH
A1
C1
E.G. DIALLED 6
E.G. NR 3 IS FREE
P wire
earthed
31
1500
A
_
+
750
Ordinary group selector 200 outlet – idle state_
+
P1
400
S2
CD5
200
N1
DIAL TONE EARTH
BUSY TONE EARTH
200
570
HA5
B6
CD6
NR2
NR3
HA2
_
+
P2
HA1
B4
B3
HB7
HB6
HB
1500 750 400
HB1
HA7
HB2
P
B5RM1
HA4HB5
NR1
RLSE
ALM
EARTH
B7
CD4
1300N2 B1
CD3
5700
RM
VM
CD2
B2
NR4
CD1
CD
B
A1
HA6HA3HB3
R2 200
R1 800
LP1
HA
R4 300
R3 500
C1
S1
32
1500
A
_
+
750
Ordinary group selector – moment of seizure – A, B and CD operate_
+
P1
400
S2
CD5
200
N1
DIAL TONE EARTH
BUSY TONE EARTH
200
570
HA5
B6
CD6
NR2
NR3
HA2
_
+
P2
HA1
B4
B3
HB7
HB6
HB
1500 750 400
HB1
HA7
HB2
P
B5RM1
HA4HB5
NR1
RLSE
ALM
EARTH
B7
CD4
1300N2 B1
CD3
5700
RM
VM
CD2
B2
NR4
CD1
CD
B
A1
HA6HA3HB3
R2 200
R1 800
LP1
HA
R4 300
R3 500
C1
S1
33
1500
A
_
+
750
Ordinary group selector – vertical stepping – N1, N2, HA and HB (750 Ohm) operate _
+
P1
400
S2
CD5
200
N1
DIAL TONE EARTH
BUSY TONE EARTH
200
570
HA5
B6
CD6
NR2
NR3
HA2
_
+
P2
HA1
B4
B3
HB7
HB6
HB
1500 750 400
HB1
HA7
HB2
P
B5RM1
HA4HB5
NR1
RLSE
ALM
EARTH
B7
CD4
1300N2 B1
CD3
5700
RM
VM
CD2
B2
NR4
CD1
CD
B
A1
HA6HA3HB3
R2 200
R1 800
LP1
HA
R4 300
R3 500
C1
S1
34
1500
A
_
+
750
Ordinary group selector – end of vertical stepping – CD releases slowly, RM operates_
+
P1
400
S2
CD5
200
N1
DIAL TONE EARTH
BUSY TONE EARTH
200
570
HA5
B6
CD6
NR2
NR3
HA2
_
+
P2
HA1
B4
B3
HB7
HB6
HB
1500 750 400
HB1
HA7
HB2
P
B5RM1
HA4HB5
NR1
RLSE
ALM
EARTH
B7
CD4
1300N2 B1
CD3
5700
RM
VM
CD2
B2
NR4
CD1
CD
B
A1
HA6HA3HB3
R2 200
R1 800
LP1
HA
R4 300
R3 500
C1
S1
35
1500
A
_
+
750
Ordinary group selector – first rotary step – RM1 breaks RM and HA/HB (750) circuits_
+
P1
400
S2
CD5
200
N1
DIAL TONE EARTH
BUSY TONE EARTH
200
570
HA5
B6
CD6
NR2
NR3
HA2
_
+
P2
HA1
B4
B3
HB7
HB6
HB
1500 750 400
HB1
HA7
HB2
P
B5RM1
HA4HB5
NR1
RLSE
ALM
EARTH
B7
CD4
1300N2 B1
CD3
5700
RM
VM
CD2
B2
NR4
CD1
CD
B
A1
HA6HA3HB3
R2 200
R1 800
LP1
HA
R4 300
R3 500
C1
ASSUME BOTH P1
AND P2 EARTHED
ON FIRST OUTLET:
HA AND HB HOLD
ON 400 OHM COIL
S1
36
1500
A
_
+
750
Ordinary group selector – free outlet found – HA and HB release, CD re-operates _
+
P1
400
S2
CD5
200
N1
DIAL TONE EARTH
BUSY TONE EARTH
200
570
HA5
B6
CD6
NR2
NR3
HA2
_
+
P2
HA1
B4
B3
HB7
HB6
HB
1500 750 400
HB1
HA7
HB2
P
B5RM1
HA4HB5
NR1
RLSE
ALM
EARTH
B7
CD4
1300N2 B1
CD3
5700
RM
VM
CD2
B2
NR4
CD1
CD
B
A1
HA6HA3HB3
R2 200
R1 800
LP1
HA
R4 300
R3 500
C1
ASSUME BOTH P1
AND P2 ARE FREE
ON SECOND
OUTLET
S1
37
1500
A
_
+
750
Ordinary group selector – connecting – A and B release, HA operates on 1500 Ohm coil _
+
P1
400
S2
CD5
200
N1
DIAL TONE EARTH
BUSY TONE EARTH
200
570
HA5
B6
CD6
NR2
NR3
HA2
_
+
P2
HA1
B4
B3
HB7
HB6
HB
1500 750 400
HB1
HA7
HB2
P
B5RM1
HA4HB5
NR1
RLSE
ALM
EARTH
B7
CD4
1300N2 B1
CD3
5700
RM
VM
CD2
B2
NR4
CD1
CD
B
A1
HA6HA3HB3
R2 200
R1 800
LP1
HA
R4 300
R3 500
C1
HA HOLDING ON
P WIRE EARTH
OF SUCCEEDING
SELECTOR
S1
38
1500
A
_
+
750
Ordinary group selector – normal release – HA and CD release, RM steps home
P1
400
S2
CD5
200
N1
DIAL TONE EARTH
BUSY TONE EARTH
200
570
HA5
B6
CD6
NR2
NR3
HA2
P2
HA1
B4
B3
HB7
HB6
HB
1500 750 400
HB1
HA7
HB2
P
B5RM1
HA4HB5
NR1
RLSE
ALM
EARTH
B7
CD4
1300N2 B1
CD3
5700
RM
VM
CD2
B2
NR4
CD1
CD
B
A1
HA6HA3HB3
R2 200
R1 800
LP1
HA
R4 300
R3 500
C1
HA RELEASES ON
FREEING OF P
WIRE OF
SUCCEEDING
SELECTOR
S1
_
+
P1
_
+
P2
39
P
2000 2000
RM
UAX13 Group Selector connected to an Ordinary Final Selector(Example: ATW 600670 connected to ATW 52160)
P
11
NR1
H
N2
S1
B3
H6HX1
N3
HX
B5
150
H7
A UAX13 GROUP SELECTOR EXPECTS A 150 OHM BATTERY
ON THE P WIRE OF A FREE FINAL SELECTOR TO OPERATE
RELAY HX.
A FREE ORDINARY FINAL SELECTOR DOES NOT PROVIDE
POWER ON ITS INCOMING P WIRE
U9
U10
U25
to Final Selector
40
P
2000 2000
RM
When group selector and final selector are both UAX13 – HX operates on 150 Ohm P wire battery
P
11
NR1
H
N2
S1
B3
H6HX1
N3
HX
B5
150
H7
P wire
on batt !!
CURRENT FLOW SHOWN IN RED, JUST
AFTER HX OPERATES ON P WIRE
BATTERY
H CONTACTS NOT YET ACTIVATED
U9
U10
U25
41
2000 2000
RM
UAX13 group selector – connecting to next selector – H operates, B and HX release
P
11
NR1
H
N2
S1
B3
H6HX1
N3
B5
150
H7
P wire gets
earthed
B RELEASES, P WIRE IS EARTHED BY
NEXT SELECTOR
H6 TAKES OVER FROM HX1
HX
P
U9
U10
U25
42
P
2000 2000
RM
Providing 150 Ohm battery
P
11
NR1
H
N2
S1
B3
H6HX1
N3
HX
B5
150
H7
TEMPORARY BATTERY CAN BE ARRANGED BY
CONNECTING AN ADDITIONAL RELAY HY BETWEEN POINTS
U9 AND U10.
RELAY B (NOT SHOWN HERE) OPERATES WHEN THE
GROUP SELECTOR IS SEIZED. IT PUTS AN EARTH TO U9.
A 150 OHM BATTERY IS ALREADY AVAILABLE ON POINT U25.
HY1 CONNECTS THE BATTERY TO THE P BANK.
THE EXTERNAL RELAY IS ACTIVATED WHEN HX OPERATES
ON TESTING A FREE FINAL SELECTOR. THAT DISCONNECTS
THE BATTERY FROM THE P WIRE. BY THAT TIME THE FREE
FINAL SELECTOR IS SEIZED.
A CAPACITOR HAS BEEN ADDED TO DELAY THE SEQUENCE.
A RELAY WITH A SLUG MAY ALSO BE USED.
U9
U10
U25
to Final Selector
HY
HY1
47uF
160V
43
P
2000 2000
RM
UAX13 group selector – additional external relay HY to provide temporary batt on P wire
P
11
NR1
H
N2
S1
B3
H6HX1
N3
HX
B5
150
H7
P wire
on batt !!
CURRENT FLOW SHOWN IN RED, JUST
AFTER HX OPERATES ON P WIRE
BATTERY
H CONTACTS AND HY1 NOT YET
ACTIVATED
RELAY HY: SONGLE SRD-48VDC-SL-C
ADDED 47uF CAPACITOR TO CONTACTS
TO SLOW THE RESPONSE
U9
U10
U25
HY1
HY
47uF
160V
44
2000 2000
RM
UAX13 group selector – connecting to ordinary selector – H and HY operate, B and HX release
P
11
NR1
H
N2
S1
B3
H6HX1
N3
B5
150
H7
P wire gets
earthed
CURRENT FLOW SHOWN IN RED, JUST
AFTER H OPERATES
B RELEASES, P WIRE EARTED BY NEXT
SELECTOR
H6 TAKES OVER FROM HX1
HX
P
U9
U10
U25
HY1
HY
47uF
160V
45