Ac Failure Mode - Nortel DMS-100 Series Maintenance Manual

ac failure mode

If both rectifiers fail and cause an FL0 and FL1 alarm, the OPM enters ac
failure mode. During ac failure mode, all battery strings are placed on the load
bus and no manual battery activities are allowed. The hardware audit
frequency now runs 15 min intervals instead of hour intervals. When the
hardware audit runs, the PESALRM card, BCCDRVR card and load bus
voltage are checked.
Post-ac failure mode (short)
An outage can cause negative results during the next test-and-charge cycle. To
prevent these negative results, the duration of the outage must not exceed 15
min. The action to take depends if power is restored in time to prevent these
results.
The system does not resume testing if
• power is restored within 12 h before the start of the test-and-charge cycle
• power is restored during the scheduled test-and-charge cycle
All strings are left on the load bus until the next charge cycle. The next charge
cycle can be the charge part of the test-and-charge cycle. If this cycle is part
of the test-and-charge cycle, charging is done, but testing does not occur.
If power is restored at another time the scheduled charging activity resumes
after a 15 min delay. If a string was on the charge bus or open-circuited, the
string is returned to that state. The next charge cycle events occur at the
scheduled times. While the occurrence of charge cycle events can result in a
short charge period, battery life will not be affected. When the OPM is in
post-ac failure mode short, P/S appears under Week at the PES MAP display.
Post-ac failure mode (extended)
If an ac outage exceeds the short ac failure interval, consider the outage an
extended ac outage. The following steps are taken:
1. All strings remain on the load bus for 24 h.
2. In sequence that starts with battery pair 0, each nonfailed equipped battery
string pair is charged for 5 h, open-circuited for 1 h and moved to the load
bus. If an unequipped or failed pair is present or if a pair fails the
minimum charge voltage test, the pair is skipped. Charging of the next
equipped, nonfailed pair starts immediately. A skipped, equipped battery
pair remains on the load bus.
3. Battery pair 3 is moved to the load bus or skipped. All strings are left on
the load bus for 24 h.
4. Audit activity resumes with the next charge period or at the beginning of
the next test-and-charge cycle. The activity resumes according to the
DMS-100 Family OPM Maintenance Manual ISN07 (TDM)/SN07 (DMS) and up
OPM maintenance summary 1-47