Type B Vital Relays - Alstom

Theory of Operation
2.4.4.3.1. Application Considerations
The AC Microchron II Timer Relay has a common registration plate to the AC Motor
Timer. The timer is designed to replace the AC Motor Timers listed in Table 2–4. The
application of the AC Motor Timer used a check circuit wired between contacts 12 and
53. This circuit consisted of two sets of contacts wired in series. The first set of relay
contacts, 11 and 12, is a back check contact of the relay structure. The second set of
contacts, 53 and 63 constitute a back check contact of the motor structure.
Figure 2–25 shows a wiring diagram for the AC Motor Timer Plugboard with the two
sets of contacts wired in series so that if one of them is open, the circuit opens.
Verifying the closure of both sets of contacts verifies the timer has reset and a full timing
cycle runs the next time power is supplied.
NOTE 1: Thin lines represent internal wiring of Relay.
Thick lines represent external Plugboard wiring.
Control
3E
4E
Test Terminal
Check Circuit
Plug Terminals
TIME
16
15
14
13
12
11
MBB
26
25
24
23
22
21
36
35
34
33
32
31
46
45
44
43
M
Motor
56
55
54
53
+
Clutch
-
CHECK
66
65
64
63
-
+
Upper Coil
(Slow Release)
Lower Coil
(Operating)
+
-
IN
OUT
IN
OUT
Plugboard Wiring
Figure 2–25. AC Motor Timer Plugboard Wiring Diagram
P1457, Rev. Nov/07 2–27 Alstom Signaling Inc.