Schneider Electric Class 615 dimensions Protection

Compact® NSF and NSJ 150 to 600 A Circuit Breakers

Section 4—Trip Units

Electronic Trip Unit STR23SP and STR23SP-OSN (Oversized Neutral)

06153065	7	1	6	3
		STR 23 SP	alarm	90 %Ir
				105

Io = sensor		long time			short time
.8	.9	Ir	.9	.93	Im	5	6
.7	1	.88		.95	4		7
.63		.85		.98	3		9
.5		.8		1	2
x In			x Io				x Ir

t

1

2

3

4

+ -

test

Ir Im

5

	0	Ir Im	I
Protection	• Long-time (LT) overload protection, adjustable threshold, based on the actual rms current

—Adjustable threshold (1) using six lo base settings (0.5–1) and fine adjustment Ir with eight settings ranging from (0.8–1)

—Non-adjustable tripping time (2)

•Short-time (ST) short-circuit protection

—Adjustable threshold Im (3)

—Fixed time delay (4)

•Instantaneous (I) short-circuit protection, fixed threshold (5)

•Neutral protection available on standard four-pole circuit breakers; protection level controlled using three-position switch

—4P 3D: no protection

—4P 3D + N/2: neutral protection at 0.5 Ir

—4P 4D: neutral protection at Ir

•Neutral protection for STR23SP-OSN (oversized neutral) available on four-pole circuit breakers equipped with oversized neutral protection; protection level controlled using three-position switch

NSJ250/400N:			NSJ400/600N:
—	4P	3D: no protection	—	4P	3D: no protection
—	4P	3D + N/2: neutral protection at 0.8 x Ir	—	4P	3D + N/2: neutral protection at 0.75 x Ir
—	4P	4D: neutral protection at 1.6 x Ir	—	4P	4D: neutral protection at 1.5 x Ir

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