Overload Relays
3
Siemens · 2011
General data
■
Overview
1) Motor currents up to 820 A can be recorded and evaluated by a current
measuring module, e. g. 3RB29 06-2BG1 (0.3 ... 3 A), in combination with
a 3UF18 68-3GA00 (820 A/1 A) series transformer.
2) The SIRIUS 3RN thermistor motor protection devices can be used to pro-
vide additional temperature-dependent protection.
Features Benefits 3RU11 3RB20/3RB21 3RB22/3RB23
General data
Sizes • Are coordinated with the dimensions, connections
and technical characteristics of the other devices
in the SIRIUS modular system (contactors, soft
starters, ...)
• Permit the mounting of slim and compact load fee-
ders in widths of 45 mm (S00), 45 mm (S0), 55 mm
(S2), 70 mm (S3), 120 mm (S6) and 145 mm
(S10/S12)
• Simplify configuration
S00 ...S3 S00 ... S12 S00 ... S12
Seamless current range • Allows easy and consistent configuration with one
series of overload relays (for small to large loads)
0.11 ... 100 A 0.1 ... 630 A 0.3 ... 630 A
(... 820 A)
1)
Protection functions
Tripping in the event of overload • Provides optimum inverse-time delayed protection
of loads against excessive temperature rises due
to overload
✔ ✔ ✔
Tripping in the event of phase
unbalance
• Provides optimum inverse-time delayed protection
of loads against excessive temperature rises due
to phase unbalance
(✔) ✔✔
Tripping in the event of phase failure • Minimizes heating of induction motors during pha-
se failure
✔ ✔ ✔
Protection of single-phase loads • Enables the protection of single-phase loads ✔ -- ✔
Tripping in the event of overheating
by
integrated thermistor motor
protection function
• Provides optimum temperature-dependent pro-
tection of loads against excessive temperature ri-
ses, e. g. for stator-critical motors or in the event of
insufficient coolant flow, contamination of the mo-
tor surface or for long starting or braking opera-
tions
• Eliminates the need for additional special
equipment
• Saves space in the control cabinet
• Reduces wiring outlay and costs
--
2)
--
2)
✔
Tripping in the event of a ground fault
by
internal ground-fault detection
(activatable)
• Provides optimum protection of loads against
high-resistance short-circuits or ground faults due
to moisture, condensed water, damage to the in-
sulation material, etc.
• Eliminates the need for additional special
equipment.
• Saves space in the control cabinet
• Reduces wiring outlay and costs
-- ✔
(only 3RB21)
✔
Features
RESET function • Allows manual or automatic resetting of the relay ✔ ✔ ✔
Remote RESET function • Allows the remote resetting of the relay ✔
(by means of sepa-
rate module)
✔
(only 3RB21 with
24 V DC)
✔
TEST function for auxiliary contacts • Allows easy checking of the function and wiring ✔ ✔ ✔
TEST function for electronics • Allows checking of the electronics -- ✔✔
Status display • Displays the current operating state ✔ ✔ ✔
Large current adjustment button • Makes it easier to set the relay exactly to the cor-
rect current value
✔✔ ✔
Integrated auxiliary contacts
(1 NO + 1 NC)
• Allows the load to be switched off if necessary
• Can be used to output signals
✔ ✔ ✔
(2 ×)
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