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"Increased safety" type of protection EEx e acc. to ATEX di-
rective 94/9/EC
The 3RB22 (monostable) solid-state overload relays are suitable
for the overload protection of explosion-proof motors with "incre-
ased safety" type of protection EEx e;
see Catalog LV 1, Chapter 20 "Appendix" --> "Standards and Ap-
provals" --> "Type Overview of Approved Devices for Explosion-
Protected Areas (ATEX Explosion Protection)".
■
Design
Device concept
The 3RB22/3RB23 solid-state overload relays are based on a
modular device concept. Each device always comprises an eva-
luation module, which is independent of the motor current, and
a current measuring module, which is dependent on the motor
current. The two modules are electrically interconnected by a
connection cable through the system interface.
The basic functionality of the evaluation module can be optio-
nally expanded with corresponding function expansion modu-
les. The function expansion modules are integrated in the evalu-
ation module for this purpose through a simple plug-in
connection.
Mounting options
Current measuring modules
The current measuring modules size S00/S0 and S2/S3 are de-
signed for stand-alone installation. By contrast, the current
measuring modules size S6 and S10/S12 are suitable for stand-
alone installation and mounting onto contactors.
Evaluation modules
The evaluation modules can be mounted either on the current
measuring module (only sizes S00/S0 and S2/S3) or separately.
For more information on the mounting options see "Technical
specifications" and Catalog LV 1, "Selection and ordering
3RB2 Solid-State Overload Relays
3RB22, 3RB23 for high-feature applications
Connection methods
Main circuit (current measuring module)
For sizes S00/S0, S2/S3 and S6, the main circuit can also be
connected by the straight-through transformer method. In this
case, the cables of the main circuit are routed directly through
the feed-through openings of the relay to the contactor
terminals.
For sizes S6 and S10/S12, the main circuit can be connected
with the help of rails. In conjunction with the corresponding box
terminals, screw connection is also possible.
Auxiliary circuit (evaluation module)
Connection of the auxiliary circuit (removable joint block) is pos-
sible with either screw or spring-type terminal connection sys-
tem (special versions).
For more information on the connection options see "Technical
specifications" and Catalog LV 1, "Selection and ordering
Overload relays in contactor assemblies
for wye-delta starting
When overload relays are used in combination with contactor
assemblies for wye-delta starting it must be noted that only
0.58 times the motor current flows through the line contactor. An
overload relay mounted onto the line contactor must be set to
0.58 times the motor current.
When 3RB22/3RB23 solid-state overload relays are used in
combination with contactor assemblies for wye-delta starting,
the function expansion modules for internal ground-fault detec-
tion must not be used.
Operation with frequency converter
The 3RB22/3RB23 solid-state overload relays are suitable for fre-
quencies of 50/60 Hz and the associated harmonics. This per-
mits the 3RB22/3RB23 overload relays to be used on the input
side of the frequency converter.
If motor protection is required on the outgoing side of the fre-
data".
quency converter, Siemens recommends the 3RN thermistor
motor protection devices or the 3RU11 thermal overload relays
for this purpose.
Overload Relays
Siemens · 2011
data".
29
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