Applications
3.3 Motor protection applications of 3VA molded case circuit breakers
3VA molded case circuit breakers with IEC certificate
Manual, 03/2019, A5E03603177010-03
163
Overload protection L:
•
I
r
Adjustable from 0.4 to 1.0 x I
n
in absolute current values
I
r
< 50 A: in steps of 0.5 A
I
r
≥
50 A: in steps of 1 A
The ETU860M has a permanently activated thermal memory.
Short-time delayed short-circuit protection S:
•
I
sd
Adjustable from 1.2 to 12/15 x I
n
in absolute current values
I
r
< 50 A: in steps of 0.5 A
I
r
≥
50 A: in steps of 1 A
•
t
sd
Permanently set to 0.03 s
Instantaneous short-circuit protection I:
•
I
i
Adjustable from 3 to 12/15 x I
n
in absolute current values
I
r
< 50 A: in steps of 0.5 A
I
r
≥
50 A: in steps of 1 A
Ground-fault protection G:
The detection of the ground-fault current is based on the vectorial summation of the three
phase currents.
•
I
g
Adjustable from 0.2 to 1 x I
n
in absolute current values
I
r
< 50 A: in steps of 0.5 A
I
r
≥
50 A: in steps of 1 A
•
t
g
Adjustable from 0.05 to 0.8 s
in steps of 0.01 s
An alarm threshold I
gA
between 0.2 to 1 x I
n
can also be set; in steps of 1 A
The current-dependent curve shape I
2
t
g
= constant can be deactivated.
Ground-fault protection (G) can be deactivated.
Note
An external current transformer for the neutral conductor cannot be connected.
Trip class T
c
or tripping time T
p
:
•
T
c
Adjustable 10 A / 10E / 20 / 20E / 30
•
T
p
Adjustable from 3 to 13 / 15 / 25 / 30 s (dependent on rated current)
in steps of 1 s
