Glossary
78
L
logs
Tables in the trip unit’s memory to store trip information,
event information, and metered value minimum/maximum values.
Log menu
The menu selection, available from the Main menu,
that allows the operator to view or reset the logs.
long time
Overcurrent protection that is only activated after a
user-defined period, typically several seconds in duration. This is
for the lowest levels of overcurrent activity.
LT
long time fault (protection).
M
Main menu
The primary menu screen on the trip unit. It
appears on powering the unit, and after pressing a key while in
idle display mode.
maintenance counter
The counter on the trip unit that keeps
track of all breaker operations, both openings and trips.
MAX Rating
The maximum amount of continuous current the
breaker is capable of carrying.
mechanical counters
The counters in the trip unit (mechani-
cal and fault) that keep track of the number of breaker operations
that are caused by manual or mechanical means and not due to
electrical fault or remote command.
metering menu
The menu selection on the Main menu that
allows the operator to view metered parameters.
min/max values
Minimum and maximum metered values.
mode switch
See
Ground Fault Mode Switch
.
model number
See
Order Number
.
MT
Multiplexer Translator. Device that allows up to eight field
devices to be attached for remote communications and/or zone
interlocking. Used with the SB Energy-Comm trip unit only for
zone interlocking.
N
NEMA
National Electrical Manufacturers Association.
O
operations
Openings or trippings of the circuit breaker.order
number
The number used to describe which model when ordering. The
order number designates which features are on the trip unit.
over amp demand alarm
The alarm signal from the trip unit
when the system exceeds a specified current demand setting.
overcurrent alarm
The alarm signal from the trip unit when the
system exceeds a user-specified current setting.
overcurrent protection
Protection provided by the trip unit
when a line current exceeds a user-specified value. Available
forms of overcurrent protection are instantaneous, short time, and
long time.
over power demand alarms
The alarm signal from the trip unit
when the system exceeds a user-specified current power value;
either over apparent power (KVA), over reactive power (KVAR) or
over real power (Over KW).
over frequency alarm
The alarm signal from the trip unit when
the system exceeds a user-specified line frequency value.
over voltage alarm
The alarm signal from the trip unit when
the system exceeds a user-specified voltage value.
P, Q
packet
SEAbus communications unit of information that is
transmitted between the field device and supervisory device.
password
A number, entered from the security menu, used to
prevent users from inadvertently changing parameters. The
default setting is no password.
period
See
Demand Period
.
phase balance
The ratio of current or voltage in a particular
phase to the average current for all three phases.
pickup
The value at which the trip unit detects a trip or alarm
condition.
power factor
The ratio of resistance to impedance. The ratio of
an actual power of an alternating current to apparent power.
Mathematically, the cosine of the angle between the voltage
applied and the current resulting.
power supply
See
External Power Supply
.
Portable Test Set
Equipment for verifying the operation of the
trip unit; for example, the TS-31 test set may be used to test the
protective functions of the SB Energy-Comm trip unit.
protective relay functions
Protective functions including trip-
ping when the system exceeds user-defined pickup values for
over and under voltage, under and over frequency, reverse power,
and unbalance.
