Murphy EMS-GC10, Operator'S Manual

Page: 60 / 183

Section 75 00-02-0878
2013-03-07 - 54 -
Mains Voltage Unbalance Detection
The formula for mains voltage unbalance is: (Most deviating line-to-line voltage -
average voltage)*100/average voltage (nominal value in %)
Phase Sequence Error
Description of Phase Sequence Error
Prior to closing a breaker, the unit checks that the phase sequence is correct,
depending on the chosen phase direction in parameter 2154: "phase rotation". If it is
incorrect (reversed), an alarm will be issued, and the breaker in question will not be
closed, and the breaker’s LED will flash red.
Breaker Types and Feedback
Breaker Types
There are five possible selections for the setting of breaker type for both mains breaker
and generator breaker.
Continuous NE and Continuous ND
This type of signal is most often used combined with a contactor. When using this type
of signal, the genset controller unit will only use the close breaker relays. The relay will
be closed for closing of the contactor and will be opened for opening of the contactor.
Continuous NE is a normally energized signal, and continuous ND is a normally de-
energized signal.
Pulse
This type of signal is most often used combined with circuit breaker. With the setting
pulse, EMS-GC10 unit will use the close command and the open command relay. The
close breaker relay will close for a short time for closing of the circuit breaker. The open
breaker relay will close for a short time for opening of the breaker.
Compact
This type of signal will most often be used combined with a compact breaker, a direct
controlled motor-driven breaker. With the setting compact, the EMS-GC10 controller
unit will need to use both a close command and a open command relay. The close
breaker relay will close for a short time for the compact breaker to close. The breaker
off relay will close for the compact breaker to open and hold it closed long enough for
the motor in the breaker to recharge the breaker. If the compact breaker is tripped
externally, it is recharged automatically before next closing.
NOTE: If compact breaker is selected, the length of breaker open
signal can be adjusted. This can be done in parameters 2160,
2170, 2180, 2200, 2210, 2220 (GB open fail and MB open fail).