Type B Vital Relays - Alstom

Theory of Operation
Group Space- Front View
6
5
4
3
2
1
1 2 3
Make-before-
Break Contact
Contact read as (Column,Row)
AC in
(Start)
Electrical
Short
4 5 6
Safety
Contacts
Medium Duty
Contacts
Figure 2–23. Relay Contacts, Front View
The unit contains two circuit boards, the Thumbwheel Switch Board and a Timer
Processor Board. The Thumbwheel Switch Board contains a five-section thumbwheel
switch to set the time and an AC to DC converter circuit. The Timer Processor Board
contains a vitally programmed 8-bit microcontroller, low voltage shutdown and
reset/watchdog Integrated Chip (IC), DC to DC converter, secondary reference clock
and vital relay driver. Figure 2–24 is a schematic of relay component interaction.
Relay Contact
Block Assembly
AC input
55
#18 WHITE
56
#18 BLACK
BLACK
OUT
OUT
Top Coil
Bottom Coil
Thumbwheel Switch Board
IN -
RED
IN + RED
3
Timer Processor
Board
1
1
J2-
J2-
2
2
31166-299-01
(110 Vrms/60 Hz)
or
31166-299-02
(55 Vrms/25 Hz)
Unregulated
31166-300-01
DC
3 (110 Vrms/60 Hz) + #18 WHITE
2
or
P2- 31166-353-01 P2-
P2-
P2-- #18 BLACK
1 (55 Vrms/25 Hz) 4
J2-
J2-
4
Figure 2–24. AC Microchron II Timer Relay Schematic
P1457, Rev. Nov/07 2–25 Alstom Signaling Inc.