Specifications

9
COMPACT
®
NS circuit breaker
Trip units for COMPACT
®
NSJ400 and NSJ600 circuit breakers
COMPACT
®
NSJ400 and NSJ600 circuit breakers are equipped with current sensors
and electronic trip units.
Current sensors
Four different sizes are available and can be mounted with all trip units:
■ NSJ400: 150, 250 and 400 A;
■ NSJ600: 600 A;
Trip units STR23SP and STR53UP
■ Protection for loads, from 60 to 600 A.
❑ STR23SP and STR53UP for standard protection;
❑ STR53UP for generator supplied network protection and for long cable runs;
■ Trip units STR23SP and STR53UP can be mounted on all COMPACT
®
NSJ400
and NSJ600 circuit breaker types N, H and L;
■ Trip unit STR53UP offers a greater number of protection settings, optional
indication and measurement functions and ground-fault protection;
■ Trip units do not have a predefined rating. The tripping threshold depends only on
the circuit breaker rating and the long-time protection setting.
For example, trip unit STR23SP, with maximum settings, has a tripping threshold of:
❑ 150 A, if mounted on a COMPACT
®
NSJ400 circuit breaker with 150 A current
sensors;
❑ 600 A, if mounted on a COMPACT
®
NSJ600 circuit breaker.
(*) If the STR23SP or STR53UP trip units are used at high operating temperature, the setting must take into account the thermal limits of the circuit breaker; the
overload protection setting cannot exceed 0.95 at 60°C or 0.90 at 70°C for the COMPACT
®
NSJ400 circuit breaker, and 0.95 at 50°C, 0.90 at 60°C and 0.85 at
70°C for the COMPACT
®
NSJ600 circuit breaker.
Trip units
COMPACT
®
NS circuit breaker: functions and characteristics
Trip units for STR23SP STR53UP
COMPACT
®
NSJ400 and NSJ600 circuit breakers
Overload protection (long time)
Tripping Ir 20 to 70°C (*) adjustable adjustable
threshold (A) (48 settings) (48 settings)
0.4–1 x In 0.4–1 x In
Tripping time (s) fixed adjustable
(min–max) at 1.5 x Ir 90–180 8–15 34–50 69–100 138–200
at 6 x Ir 5–7.5 0.4–0.5 1.5–2 3–4 6–8
Short-circuit protection (short time)
Tripping Im adjustable adjustable
threshold (A) (8 settings) (8 settings)
2–9 x Ir 1.5–7 x Ir
accuracy ± 15% ± 15%
Time delay (ms) max. overcurrent fixed adjustable (4 settings + constant I
2
t function)
time before tripping ≤ 40 ≤ 15 ≤ 60 ≤ 140 ≤ 230
total breaking time ≤ 60 ≤ 60 ≤ 140 ≤ 230 ≤ 350
Short-circuit protection (instantaneous)
Tripping fixed adjustable (8 settings)
Threshold (A) ≥ 9 x In 1.5–7 x In
Other functions
Indication of type of fault ■ (standard)
"Ground-fault" protection (T) ■
Built-in ammeter (I) ■
Zone-selective interlocking (ZSI) ■
Communication (COM) ■