Rockwell Automation 1608M MegaDySC User Manual, 208 Volt, One Second Extended Runt - Manual (Page 45)

Rockwell Automation Publication 1608M-UM004A-EN-P - April 2014 45
Maintenance Chapter 7
Servicing
Before attempting any servicing that requires opening the MegaDySC doors first
put the system into Maintenance Bypass mode as described in the section
Automatic Bypass Switchboard Operation on page 22
Automatic Circuit Breakers, Safety Interlocks and Stored Energy
Figure 9 on page 24 shows the arrangement of circuit breakers CBI, CBO, and
CBB of the Automatic Bypass switchboard. If the MegaDySC cabinet door is
opened while the system is operating in normal mode the circuit breaker CBB
will automatically close and CBI and CBO will be automatically opened, putting
the system into maintenance bypass mode until it is manually reset. The ER
module will be electrically disconnected from the MegaDySC module. Voltage
sag protection is not possible in the maintenance bypass mode. All doors should
be kept locked to avoid this situation.
If the ER module door is opened, the ER module will be electrically disconnected
from the MegaDySC cabinet and the energy storage capacitors will be
discharged. The MegaDySC system will remain in the normal mode. Limited sag
protection will be available; however, the energy stored in the ER module will
not be available to the sag correction electronics. All doors should be kept locked
to avoid this situation.
The ER module door has both mechanical key locks as well as an electronic lock.
The electronic lock is controlled by the MegaDySC system. The electronic lock
will only be released when it is safe to open the ER module door. A light on the
front of the ER module door will indicate if the ER module door has been
unlocked by the MegaDySC system. If control power to the MegaDySC system is
interrupted, the ER module door will remain locked.
The MegaDySC includes a fast-discharge circuit to quickly dissipate stored
energy in the MegaDySC module and the ER module. Stored energy in the
MegaDySC module is discharged when the circuit breaker CBI is opened. CBI
may be operated automatically by the door interlock switches or other protection
devices. CBI can also be operated manually. Stored energy in the ER module is
discharged when the ER module door is opened.
ATTENTION: Service must be performed by qualified personnel only.
WARNING: The MegaDySC cabinet is interlocked. Opening cabinet doors while
in the MegaDySC “normal” mode will cause immediate automatic bypass
operation and subsequent loss of voltage sag protection while in “maintenance
bypass” mode. Automatic Bypass switchboard cabinet doors are not interlocked
and should be kept locked to avoid exposure to dangerous voltages.