2 Engineering
2.3 Short-circuit protection of the overload relays
36
ZB12-…, ZB32-…
11/16 MN03407004Z-DE/EN
www.eaton.com
Example
I
A
/I
N
= 6, t
E
= 10 s
Figure 6: Tripping characteristic of the overload relay
The motor is reliably protected.
2.3 Short-circuit protection of the overload relays
The overload relays are short-circuit protected by means of fuses.
When the relay is mounted directly onto a contactor relay, the corresponding
primary fuse of the contactor relay is taken into account accordingly.
1
0.1
0.2
0.4
0.6
0.8
1
2
4
6
8
10
20
40
1
2
4
6
8
10
2
3
4
5
6
7 8 9 10
J
min
s
N
1
CAUTION
According to EN 60947-4-1 only type of coordination “2” may
be used for the protection of EEx e motors.
