Multifunction Protection and Switchgear Control unit REF542plus
Manual: Motor Protection with ATEX-Certification
10 Appendix:
The tripping characteristics for the thermal overload protection depending on
the setting of the time constant with constant k and the preloading as parame-
ter are summarized. According to [DIN1] the preloading is assumed to be 0%
(cold start), 90% and 100% (nominal condition) each time. In the figure the pa-
rameter for the time constant is named as Zkf instead of TC.
Note To show the flexibility of the thermal overload protection the tripping characteristics
are represented according the whole range of setting parameter of the time constant
Zkf or better TC. For practical application is in general a setting range between 200
and 2000s sufficient.
k = 1,05 with 0% preloading
0,1
1
10
100
1000
10000
100000
0,5
1,0
1,5
2,0
2,5
3,0
3,5
4,0
4,5
5,0
5,5
6,0
6,5
7,0
7,5
8,0
8,5
9,0
9,5
10,0
I/IB
Time in s
TC=20s TC=200s TC=2000s TC=20000s
1VTA100114-Rev. 04 en PTMV, 19.01.05 Motorprotection 59 / 66
Valid from Version V4D02
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