I.B. 29C891B
Page 15
Effective 11/98
All rating plugs are designed with a rejection feature to
prevent interchanging between different circuit breaker
types. In addition, the circuit breaker will trip if a rating
plug is removed with the trip unit energized.
BEFORE A RATING PLUG IS INSTALLED INTO THE
TRIP UNIT, BE CERTAIN TO CHECK THAT THE
BREAKER TYPE AND FRAME RATING (OR SENSOR
RATING IF APPLICABLE) MATCH THOSE PRINTED
ON THE RATING PLUG COVER. INSTALLING A
RATING PLUG THAT DOES NOT MATCH THE
BREAKER TYPE AND FRAME RATING (OR SENSOR
RATING IF APPLICABLE) CAN PRODUCE SERIOUS
MISCOORDINATION AND/OR FAILURE OF THE
PROTECTION SYSTEM.
IN ADDITION, IT IS IMPORTANT TO MAKE SURE
THAT A RATING PLUG IS PROPERLY INSTALLED
AND SECURED TO ENSURE PROPER FUNCTION-
ING OF THE CIRCUIT BREAKER.
2-7 EXTERNAL OPTIM TRIP UNIT ACCESSORIES
Digitrip OPTIM Trip Units for K, L, and N-Frame circuit
breakers utilize a number of accessory items mounted
outside the circuit breaker (Figure
2-14
). R-Frame, SPB
and DSII circuit breakers have these devices already
installed internally. Refer to Table
2.2
for specific
accessory details, catalog numbers and/or approved
accessory items.
Figure 2-14 Power Accessory Requirements for K, L and N-Frame Circuit Breakers
OPTIM 750 Trip Unit
OPTIM 1050 Trip Unit
(Requires)
(Requires)
R
EMOTELY
M
OUNTED
24 VDC P
OWER
S
UPPLY
R
EMOTELY
M
OUNTED
24 VDC P
OWER
S
UPPLY
and
P
OTENTIAL
T
RANSFORMER
M
ODULE
(PTM)
Circuit
Breaker
Type
Series C L-Frame
and
Series C N-Frame
24 VDC
Power
Supply
N-Frame
L-Frame
24 VDC
Power
Supply
N-Frame
L-Frame
PTM
Control Power Source
K, L, and N-Frame circuit breakers with OPTIM Model
750 or 1050 Trip Units utilize 24 Vdc control power from
an external source for IMPACC communications. The
power supply needs to be a high quality, “isolated” type
for best performance.
Potential Transformer Module (PTM)
All Digitrip OPTIM 1050 Trip Units require a potential
transformer module to provide voltage for power and
energy monitoring, and the power factor display. K, L
and N-Frame circuit breakers utilize an externally
mounted potential transformer module, which can feed
up to 16 circuit breakers (Figure
2-15
).
Ground Fault Alarm Indicator
K, L and N-Frame circuit breakers with OPTIM 750/1050
Trip Units utilize a remotely mounted ground fault alarm
indicator (Figure
2-16
). This unit provides an indicator
light and relay contacts to operate other warning
devices when a ground fault condition occurs. Model
550 OPTIM does not support this feature.
2-8 SPECIFICATION AND PROTECTIVE RANGE
SUMMARIES
Refer to Tables
2.2, 2.3, 3.2
and
3.3
for trip unit/acces-
sory specification details and trip unit protective ranges.
WARNING
Summary of Contents for Digitrip OPTIM 1050
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