Rockwell Automation 1608M MegaDySC User Manual, 800 - 2400 A - Manual (Page 38)

38 Rockwell Automation Publication 1608M-UM002A-EN-P - September 2013
Chapter 7 Maintenance
Servicing
Refer to the Hardware Service Manual for detailed instructions. 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 20
Automatic Circuit Breakers, Safety Interlocks and Stored Energy
Figure 7 on page 22 shows the arrangement of circuit breakers CBI, CBO, and
CBB of the Automatic Bypass switchboard. If the MegaDySC cabinet doors are
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. Voltage sag
protection is not possible in the maintenance bypass mode. All doors should be
kept locked to avoid this situation.
The MegaDySC includes a fast-discharge circuit to quickly dissipate stored
energy 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.
If the upstream power is interrupted before CBI is opened the fast-discharge
circuit will not be triggered. In that case wait at least 30 minutes before opening
the MegaDySC cabinet or ER cabinet doors to avoid exposure to charged
capacitors. High voltage remains on capacitors if the red LED indicators above
the module capacitor banks are lighted.
Fuses Fast-acting fuses are included to protect the MegaDySC system in the event of a
load-short circuit or other conditions. Fuses are located within the Automatic
Bypass switchboard cabinet, the MegaDySC cabinet and the optional ER storage
cabinet. To maintain protection of the MegaDySC system, fuses must be replaced
with the same or exact replacement type. Replacement fuses are available through
Rockwell Automation Technical Support and should only be replaced by
qualified and factory authorized service personnel.
ATTENTION: Service must be performed by qualified personnel only.
WARNING: The MegaDySC and optional ER cabinets are 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.