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New generation IZM97, 99 low voltage air circuit breaker instruction manual
MN013010EN February 2020 www.eaton.com.cn
Section 6: Protective characteristic curves
IZM97(99)...V(U)...PXR20/25 Long Delay(L) and Short Delay(S) Curves
S-Protection with: I²t-Characteristic curve ON
.01
.02
.03
.04
.05
.06
.07
.08
.09
.1
.2
.3
.4
.5
.6
.7
.8
.9
1
2
3
4
5
6
7
8
9
10
20
30
40
50
60
70
80
90
100
1
2
3
4
5
6
7
8
9
10
20
30
40
50
60
70
80
90
100
200
300
400
500
600
700
800
900
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
24
4
15
2
7
0.5
1.5
10
6
0.5
0.1
0.3
0.4
1
3
0.5
Time in
Sec
onds
Current in Multiples of Long Delay Pickup (I
r
)
Notes:
1. This curve shown as a multiple of the LONG PU setting(I
r
). The actual pickup point occurs at 110% of the I
r
, with ±5% tolerance.
2. SDPU = 1.5x to 10x of I
r
, have 100% ± 10% tolerance.
3. LD Time = 0.5s to 24s, have 100% +0 / -30% tolerance.
4. SD Slope = I²T. The short pickup points have ±10% tolerance.
time setting from 0.1s to 0.5s, with steps of 0.1s, except 0.2s.
tolerance is 100% +0 / -30% except 0. 1s, has tolerance 100% +0 / -40%.
5. I²T slopes flattens out at 8x of I
r
for top of band with FLAT time minimum value prevailing for bottom of band. For all curves the lower flat
response time value projected to I²T line will determine the other break point and shape of the curve.
6. If long delay thermal memory is enabled, trip times may be shorter than indicated in this chart.
7. Curves applies from -20°C to +50°C ambient. Temperatures above +85°C will cause over temperature trip.
8. This curve is for 50Hz, 60Hz applications.
9. These curves are comprehensive for series IZM97/99 circuit breakers including all frame sizes, ratings, and constructions.
