Table 4.1 Sensor and Limiter Ratings
Breaker Sensor Limiter Ratings
Type Rating ø Recommended *Minimum **Maximum
DSLII-308 800A 1600A 1200A 2000A
DSLII-308 600A 1200A 800A 2000A
DSLII-308
Less than
1200A 125% or more 2000A
600A of sensor rating
DSLII-516 1600A 3000A 3000A 3000A
DSLII-516 1200A 2500A 2000A 3000A
DSLII-516
Less than
2000A 125% or more 3000A
1200A of sensor rating
DSLII-620 2000A 3000A 3000A 3000A
ø Minimizes nuisance blowing of limiters
* Use only when current limiting is required for downstream equip-
ment. If long delay pick-up is set above 100%, minimum limiter
ratings should not be used.
** Highest rating that will protect breaker.
trucks. They are used in series with DSII-632 and DSII-840
circuit breakers respectively. This separate mounting is made
necessary by the size of the fuses and their high tempera-
ture characteristics.
4-6.1 DSLII Current Limiters
Do not replace limiters with sizes other than permitted by
Table 4.1. DSLII current limiters have been tested and ap-
proved by Underwriters Laboratories, Inc. for use in DSLII
circuit breakers when applied according to Table 4.1. They
are not electrically or physically interchangeable with current
limiting fuses of any other design.
The current limiters are held in place in an extension
provided on the back of the circuit breaker (Figure 4-16).
This extension makes the DSLII circuit breaker eight inches
deeper than the corresponding DSII circuit breaker. The cur-
rent limiters can only be removed from the circuit breaker
and replaced when the circuit breaker is removed from its
associated compartment. For this reason there is no fixed
mounted version of the DSLII circuit breaker.
4-6.2 Blown Limiter Indicator
The blown limiter indicator provides a visual indication on the
front of the DSLII circuit breaker when a current limiter in
any phase has interrupted a short circuit. It also insures that
the circuit breaker will be tripped when any current limiter
has blown. This prevents single phase power from being ap-
plied to a three-phase load (Figure 4-17).
Figure 4-16 DSLII-516 Circuit Breaker (Side View)
The indicator device consists of three solenoids, each con-
nected in parallel with one of the limiters. When a limiter is
blown, the resulting voltage across the open limiter causes
the associated solenoid to operate. Operation of the sole-
noid trips the circuit breaker mechanically and extends an
indicator through the front cover of the circuit breaker (Fig-
ure 3-2). The indicator will remain extended and the breaker
will be held trip-free until the reset button is pushed. If the
device is reset and the breaker reclosed on an energized
circuit before the blown limiter is replaced, the breaker will
immediately be reopened and held trip-free. The solenoids
are isolated from the primary circuit voltage by three trans-
formers located above the limiters (Figures 3-2 and 4-16).
4-6.3 Fuse Truck
DSII-FT32 and DSII-FT40 fuse trucks provide drawout mount-
ing for current limiting fuses when installed in low voltage
switchgear. These drawout trucks physically fit in the same
compartment as the DSII-632 and DSII-840 circuit breakers
respectively. They are moved in and out of the compartment
using a similar levering mechanism as provided on DSII
circuit breakers (Figure 4-18 and 4-19).
Effective July 2010
Instructional Book IB694C694-03
48
EATON CORPORATION www.eaton.com
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