Configuration
4.6 Load feeders - protection against short circuit
SIRIUS 3RM1 motor starter
Manual, 06/2016, A5E0345285095020A/RS-AE/005
71
Combining 3RM1 motor starters with miniature circuit breakers
DANGER
Hazardous voltage at the motor
Will cause death, serious injury, or damage to property.
Health hazard from automatic hot restart.
The safety function must be checked after every tripping of the motor starter protector (also
in the case of overload).
After every short circuit in the case of short-circuit protection according to type of
coordination 1, a 3RM1 motor starter is defective.
Replace a 3RM1 motor starter including the terminals after a short circuit in the case of
short-circuit protection according to type of coordination 1.
With 3RM11 / 3RM13 Failsafe motor starters, you must check the safety functions in
addition to replacing the unit.
With 3RM11 / 3RM13 Failsafe motor starters, check the safety functions after a short circuit
in the case of short-circuit protection according to type of coordination 2.
The 3RM1 motor starters can be combined with the following miniature circuit breakers for
short circuits according to type of coordination 1:
Table 4- 7
Miniature circuit breakers according to type of coordination 1 for 3RM1 motor starters
with 400 V
Motor starter T
A
= 40 °C
Short-circuit
current
Maximum permitted miniature circuit
breakers
with 400 V + 10%
Article number
Rated current [A] Current [kA]
Article number
Rated current [A]
3RM1.01…
0.5
6
5SY4325-6
25
3RM1.02…
2.0
6
5SY4325-6
25
3RM1.07…
7.0
6
5SY4325-6
25
4.6.3.2
Fused design
On tested assemblies, the type of coordination defines the permissible condition of devices
following a short-circuit.
Type of coordination 1 means that the load feeder may be non-operational after a short
circuit has been cleared.
Type of coordination 2 means that the 3RM1 motor starter is still operational following a
short-circuit.
With the 3RM1 motor starter, short-circuit protection is only provided by fuses up to 400 V
(+10%) for type of coordination 2.
