Description
3.5 Functions
SIRIUS 3RM1 motor starter
Manual, 06/2016, A5E0345285095020A/RS-AE/005
35
3.5.2
Protective functions
3.5.2.1
Overload protection
The 3RM1 motor starter protects three-phase motors against overload. If the current
exceeds the set value, the 3RM1 motor starter switches off within the specified tripping time
and signals the fault via the LEDs and the fault signaling output. You will find the tripping
characteristic in the chapter "Overload protection/device protection characteristic
(Page 145)".
Note
ATEX-certified motor overload protection in the case of 3RM11/3RM13 Failsafe
Overload protection of safety-related 3RM11 Failsafe and 3RM13 Failsafe motor starters is
ATEX-certified up to SILCL 2; see Chapter "ATEX-certified motor overload protection in the
case of 3RM11/3RM13 Failsafe (Page 38)."
3.5.2.2
Equipment protection
In addition to the motor protection function, the 3RM1 motor starters also protect themselves
against overload. This means that in the case of 3RM1 motor starters with a rated
operational current of 7 A, an overload trip may occur in the upper current range before the
motor protection trips.
If, for example, 8-fold current flows in the case of an unloaded motor memory module and a
set current of 7 A, tripping takes place after approximately one second.
You will find the tripping characteristic in the chapter "Overload protection/device protection
characteristic (Page 145)".
3.5.2.3
Phase failure protection
The 3RM1 motor starter is provided with phase failure protection to prevent excessive
temperature rise in the load in double phasing if phase failure occurs.
Depending on whether the phase failure already occurs before the ON command or during
the ON state, the devices respond as described in the table and signal a phase failure.
Standard motor starters
3RM10/3RM12
Failsafe motor starters
3RM11/3RM13
Phase failure before the ON
command
The motor starter switches off
after 5 s.
The motor starter does not
switch on.
Phase failure during the ON
state
The motor starter switches off
after 5 s.
The motor starter switches off
after 5 s.
