Type B Vital Relays - Alstom

Theory of Operation
A jumper on the AC Microchron II Timer Relay has replaced the motor back check
contact that existed between contacts 53 and 63 in the AC Motor Timer. The new AC
Microchron II Timer Relay inherently provides full “set” time from the instant energy is
applied; therefore, no “motor” back check contact is required for this function.
2.4.4.3.2. Replaceable AC Motor Timers
With proper installation, the AC Microchron II Timer Relay can replace certain AC Motor
Timers. Table 2–4 shows the AC Motor Timers it can replace.
WARNING
THE AC MICROCHRON II TIMER RELAY MAY NOT BE
INTERCHANGEABLE WITH A MOTOR-OPERATED TIMER IN EVERY
CIRCUIT APPLICATION BECAUSE OF THE FOLLOWING DIFFERENCE
BETWEEN THE TWO TIMERS:
• AC MICROCHRON II TIMER RELAY - CHECK CIRCUIT OPENS
AFTER TIME DELAY HAS EXPIRED, AND CLOSES WHEN POWER
IS REMOVED
• AC MOTOR TIMER - CHECK CIRCUIT OPENS AT BEGINNING OF
TIME DELAY AND CLOSES WHEN POWER IS REMOVED
Table 2–4. Replaceable AC Motor Timers
AC Microchron II Timer Relay Part Number
50800-103-01 (60 HZ operation)
50800-104-01 (25 Hz operation)
AC Motor Timer Part Number
56007-050-01
56007-051-01
56007-060-01
56007-061-01
56007-066-01
56007-067-01
56007-067-02
56007-068-01
56007-068-02
56007-062-01
56007-063-01
56007-065-01
56007-069-01
56007-070-01
P1457, Rev. Nov/07 2–28 Alstom Signaling Inc.