Rockwell Automation 1608M MegaDySC User Manual, 400 A - Manual (Page 25)

Rockwell Automation Publication 1608M-UM001A-EN-P - September 2013 25
Operation Chapter 5
Normal Mode
The NORMAL mode for the MegaDySC is Input Breaker (CBI) and Output
Breaker (CBO) closed. The bypass breaker (CBB) must be open or the
MegaDySC will not be able to correct voltage sags. There is a red indicator light
on the bypass enclosure that is lighted when the bypass is closed. The green "OK"
status box should be shown on the touchscreen display. The green "OK" box
indicates that the voltage at the output of the MegaDySC is within the +10%, -
13% normal window. Refer to
Table 2 for operational conditions and indications.
Bypass Mode
The BYPASS mode for the MegaDySC is for Input Breaker (CBI) and Output
Breaker (CBO) to be open. The bypass breaker (CBB) must be closed to provide
power to the load while the MegaDySC is being serviced.
Refer to
Automatic Bypass Switchboard Operation on page 22 for the placard on
the bypass switchboard for instructions on transferring the system into and out of
bypass mode.
Test Mode
The TEST mode for the MegaDySC is for Input Breaker (CBI) to be closed and
Output Breaker (CBO) to be open. The bypass breaker (CBB) must be closed to
provide power to the load while the MegaDySC is being tested off-line.
Fault Protection
Fault protection is provided by a variety of protection devices including
electronic, circuit breakers and fuses.
CBI and CBO are set to protect the MegaDySC conductors. If an upstream
circuit breaker is present, CBB is typically coordinated to allow the upstream
breaker to be the primary protection for the branch circuit.
The MegaDySC section contains semiconductor fuses rated 800 A. These fuses
provide short circuit protection for the MegaDySC modules. In the event of a
short circuit, this fuse will clear and trigger an automatic transfer to mechanical
bypass mode.
In addition, each module has an electronic current limit function that will
WARNING: Servicing must only be performed by factory authorized and
qualified personnel.
WARNING: Testing must only be performed by factory authorized and qualified
personnel.