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Compact® NSF and NSJ 150 to 600 A Circuit Breakers
Section 4—Trip Units
© 1995–2003 Schneider Electric All Rights Reserved
11
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,
STR53UP and
STR23SP-OSN
•
Protection for loads, from 60 to 600 A
— STR23SP and STR53UP for standard protection
— STR23SP-OSN for oversized neutral protection (factory-installed only)
— STR53UP for generator supplied network protection and 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 optional indication and measurement functions,
protection settings and ground-fault protection
• STR23SP and STR53UP available on four-pole circuit breakers with sealable, 3-position neutral
protection setting:
— 4P 3D (neutral unprotected)
— 4P 3D + N/2 (neutral protection at 0.5 x Ir) where Ir is trip unit current setting
— 4P 4D (neutral protection at Ir) where Ir is trip unit current setting
Trip Units for Compact
®
NSJ400 and NSJ600
Circuit Breakers
STR23SP STR53UP
STR23SP OSN
(Oversized Neutral)
Overload Protection (Long Time)
Tripping
Threshold (A)
Ir
20–70° C Adjustable (48 Settings) 0.4–1 x In
Tripping Time (s)
(Min–Max)
Fixed Adjustable Fixed
At 1.5 x Ir 120–180 17–25 34–50 69–100 138–200 277–400 120–180
At 6 x Ir 5–7.5 0.8–1 1.6–2 3.2–4 6.4–8 12.8–16 5–7.5
At 7.2 x Ir 3.2–5.0 0.5–0.7 1.1–1.4 2.2–2.8 4.4–5.5 8.8–11 3.2–5.0
Short-circuit Protection (Short Time)
Tripping
Im / Isd
Adjustable (7 Settings)
2–9 x Ir
Adjustable (7 Settings) 1.5–7 x Ir Adjustable (7 Settings) 2–9 x Ir
Accuracy ± 15%
Time Delay
(ms)
Max. Overcurrent Time Before Tripping Fixed ≤ 40
Adjustable (4 Settings + Constant I
2
t Function)
Fixed ≤ 40
≤ 15 ≤ 60 ≤ 140 ≤ 230
Total Breaking Time ≤ 60 ≤ 60 ≤ 140 ≤ 230 ≤ 350 ≤ 60
Short-circuit Protection (Instantaneous)
Tripping Threshold (A)
Fixed ≥ 9 x In Adjustable (7 Settings) 1.5–9 x In Fixed ≥ 9 x In
Adjustable Neutral Protection (Three Position Switch)
NSJ250/400N NSJ400/600N
Switch Settings Protection Level
Position 1 4P 3D No Protection No Protection No Protection No Protection
Position 2 4P 3D + N/2 0.5 x Ir 0.5 x Ir 0.8 x Ir 0.75 x Ir
Position 3 4P 4D 1.0 x Ir 1.0 x Ir 1.6 x Ir 1.5 x Ir
Other Functions
Indication of Fault Type ■ (Standard)
Equipment Ground-fault Protection (T) ■
Built-in Ammeter (I) ■
Zone-selective Interlocking (ZSI) ■
Communication (COM) ■