4 Short-circuit / motor protection
4.2 Motor protection
EMS2…-SWD Electronic motor starter
10/19 MN120008EN
www.eaton.com
33
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 3 A are in trip class 10.
Figure 10:Tripping characteristics class 10
t = tripping time
I = actual motor current
I
n
= setting of the motor protection on the EMS2-…-SWD device
Devices with a rated operational current I
e
of 9 A are in trip class 10A.
Figure 11:Tripping characteristics class 10A
t = tripping time
I = actual motor current
I
n
= setting of the motor protection on the EMS2-…-SWD device
WARNING
Below the minimum device current, the motor on the
EMS2-…-SWD motor starter is ineffective.
￫
In the delivery state, the motor protection is set to the lowest
value (see also the following Section).
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]
