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Overload Relays
3RB2 Solid-State Overload Relays
3RB22, 3RB23 for high-feature applications
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Overview
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3RB22/3RB23 evaluation module
(1)Green "READY" LED:
A continuous green light signals that the device is working correctly.
(2)Red "GND FAULT" LED
A continuous red light signals a ground-fault tripping.
(3)Red "THERMISTOR" LED:
A continuous red light signals an active thermistor trip.
(4)Red "OVERLOAD" LED:
A continuous red light signals an active overload trip; a flickering red
light signals an imminent trip (overload warning).
(5)Motor current and trip class setting:
Setting the device to the motor current and to the required trip class de-
pendent on the start-up conditions is easy with the two rotary switches.
(6)Selector switch for manual/automatic RESET:
With this switch you can choose between manual and automatic
RESET.
(7)TEST/RESET button:
Enables testing of all important device components and functions, plus
resetting of the device after a trip when manual RESET is
selected.
(8)Connecting terminals (removable joint block):
The generously sized terminals permit connection of two conductors
with different cross-sections for the auxiliary, control and sensor circuits.
Connection is possible with screw connection and alternatively with
spring-type connection.
(9)3RB29 85 function expansion module:
Enables more functions to be added, e. g. internal ground-fault detec-
tion and/or an analog output with corresponding signals.
3RB29 06 current measuring module
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Siemens · 2011
The modular, solid-state overload relays with external power sup-
ply type 3RB22 (with monostable auxiliary contacts) and type
3RB23 (with bistable auxiliary contacts) up to 630 A (up to 820 A
possible with a series transformer) have been designed for in-
verse-time delayed protection of loads with normal and heavy st-
arting
(see "Function")
overload, phase unbalance or phase failure. An overload, phase
unbalance or phase failure result in an increase of the motor cur-
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rent beyond the set rated motor current. This current rise is detec-
ted by means of a current measuring module and electronically
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evaluated by a special evaluation module which is connected to
it. The evaluation electronics sends a signal to the auxiliary con-
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tacts. The auxiliary contacts then switch off the load by means of
a contactor. The break time depends on the ratio between the trip-
ping current and current setting I
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long-term stable tripping characteristic
ves"). The "tripped" status is signaled by means of a continuous
red "
OVERLOAD
The LED indicates imminent tripping of the relay due to overload,
phase unbalance or phase failure by flickering when the limit cur-
rent has been violated. This warning can also be issued as a sig-
nal through auxiliary contacts.
In addition to the described inverse-time delayed protection of
loads against excessive temperature rises, the 3RB22/3RB23
solid-state overload relays also allow direct temperature monitor-
ing of the motor windings (full motor protection) by connection
with short-circuit and open-circuit detection of a PTC sensor cir-
cuit. With this temperature-dependent protection, the loads can
be protected against overheating caused indirectly by reduced
coolant flow, for example, which cannot be detected by means of
the current alone. In the event of overheating, the devices switch
off the contactor, and thus the load, by means of the auxiliary con-
tacts. The "tripped" status is signaled by means of a continuously
illuminated "
To also protect the loads against high-resistance short-circuits
due to damage to the insulation, humidity, condensed water, etc.,
the 3RB22/3RB23 solid-state overload relays offer the possibility
of internal ground-fault detection in conjunction with a function ex-
pansion module
"Selection and ordering data";
contactor assembly for wye-delta starting). In the event of a
ground fault the 3RB22/3RB23 relays trip. The "tripped" status is
signaled by means of a continuous red "
ing through auxiliary contacts is also possible.
After tripping due to overload, phase unbalance, phase failure,
thermistor or ground-fault tripping, the relay is reset manually or
automatically after the recovery time has elapsed
"Function").
In conjunction with a function expansion module the motor current
measured by the microprocessor can be output in the form of an
analog signal 4 ... 20 mA DC for operating rotary coil instruments
or for feeding into analog inputs of programmable logic control-
lers. With an additional AS-Interface analog module the current
values can also be transferred over the AS-i bus
system.
The devices are manufactured in accordance with environmental
guidelines and contain environmentally friendly and reusable ma-
terials.
They comply with all important worldwide standards and
approvals.
against excessive temperature rises due to
and is stored in the form of a
e
(see "Characteristic Cur-
" LED.
" LED.
THERMISTOR
(for details see Catalog LV 1,
not possible in conjunction with
GND FAULT
" LED. Signal-
(see
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