Type B Vital Relays - Alstom

Theory of Operation
Table 2–3 summarizes the AC Microchron II Timer Relay operating characteristics.
Table 2–3. AC Microchron II Timer Relay Operating Characteristics
Relay 50800-103-01 50800-104-01
Input Voltage
Range
Input Power While
Timing
88 to 135 Vrms, 60 Hz AC 44 to 66 Vrms, 25 Hz AC
11 mA rms at 88 Vrms
18 mA rms at 110 Vrms
44 mA rms at 135 Vrms
23 mA rms at 44 Vrms
54 mA rms at 55 Vrms
161 mA rms at 66 Vrms
Input Power After
Timing with Relay
Energized
26 mA rms at 88 Vrms
27 mA rms at 110 Vrms
45 mA rms at 135 Vrms
52 mA rms at 44 Vrms
61 mA rms at 55 Vrms
148 mA rms at 66 Vrms
The Timer Processor Board interfaces with the Thumbwheel Switch Board through a PC
edge connector. The four-wire connector on the Thumbwheel Switch Board is used to
provide AC power to the AC to DC converter (two wires), and route unregulated DC
power to the Timer Processor Board (two wires).
Vital software verifications continuously check the result of the microcontroller’s and
supporting hardware’s functions. The microcontroller electronically energizes the relay
coils after a set time delay interval has been reached. Any interruption of power to the
relay causes the unit to reset and immediately return to the beginning of the timing
interval.
Indicators on the unit include a red LED that pulses during the timing cycle and
becomes steady when the timing cycle is complete. A green LED illuminates at the
completion of the timing cycle.
P1457, Rev. Nov/07 2–26 Alstom Signaling Inc.