4 Short-circuit / motor protection
4.2 Motor protection
EMS2… Electronic motor starter
10/19 MN034003EN
www.eaton.com
27
4.2 Motor protection
Themotor protection prevents the connected motor from heating up too
much if the actual motor current is greater than the specified rated current
(i. e. I > I
n
). The time up until tripping depends on the current and the trip
class.
Devices with a rated operational current I
e
of 2.4 A or 3 A are in trip class 10.
Figure 15: Tripping characteristics class 10
t = tripping time
I = actual motor current
I
n
= setting of the motor protection on the EMS2 device
Devices with a rated operational current I
e
of 9 A have the tripping class 10A.
Figure 16: Tripping characteristics class 10A
t = tripping time
I = actual motor current
I
n
= setting of the motor protection on the device EMS2
t [s]
1
2
3
4
5
6
7
8
9
10 I / I
n
1
10
100
1000
60
40
30
20
600
400
300
200
6
4
3
2
0.6
0.4
0.3
0.2
0
Class 10
1
2
3
4
5
6
7
8
9
10 I / I
n
1
10
100
1000
60
40
30
20
600
400
300
200
6
4
3
2
0.6
0.4
0.3
0.2
0
Class 10 A
t [s]
