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Recovery time
With the 3RB22/3RB23 solid-state overload relays the recovery
time after inverse-time delayed tripping is approx. 3 minutes re-
gardless of the selected reset mode. The recovery time allows
the load to cool down.
However, in the event of temperature-dependent tripping by me-
ans of a connected PTC sensor circuit, the device can only be
manually or automatically reset once the winding temperature at
the installation location of the PTC thermistor has fallen
5 Kelvin below its response temperature.
After a ground-fault tripping the 3RB22/3RB23 solid-state over-
load relay trips can be reset immediately without a recovery time.
TEST function
The combined TEST/RESET button can be used to check whe-
ther the relay is working correctly. The test can be aborted at any
time by letting go of the TEST/RESET button.
LEDs, the device configuration (this depends on which expan-
sion module is plugged in) and the device hardware are tested
while the button is kept pressed for 6 seconds. Simultaneously
and for another 18 seconds a direct current proportional in size
to the maximum phase of the main current is fed in at the termi-
nals I(+) and I(-). By comparing the analog signal, which is to be
measured, with the main current, the accuracy of the current
measurement can be determined. In this case 4 mA corres-
ponds to 0 % and 20 mA to 125 % of the current setting. After 24
seconds the auxiliary contacts are switched and the feeder
switch off as the result, bringing the test to an end.
After a test trip a faultless relay is reset by pressing the TEST/
RESET button. If a hardware fault is detected, the device trips
and cannot be reset.
Self-monitoring
The 3RB22/3RB23 solid-state overload relays have a self-moni-
toring feature, i. e. the devices constantly monitor their own ba-
sic functions and trip if an internal fault is detected.
Display of the operating state
The particular operating state of the 3RB22/3RB23 solid-state
overload relays is displayed by means of four LEDs:
• Green "
" LED: A continuous green light signals that the
READY
overload relay is ready for operation. The 3RB22/3RB23 over-
load relays are not ready (LED "OFF") if there is no control sup-
ply voltage or if the function test was negative.
• Red "
" LED: A continuous red light signals a ground
GND FAULT
fault.
• Red "
" LED: A continuous red light signals a tem-
THERMISTOR
perature-dependent trip.
• Red "
" LED: A continuous red light signals an in-
OVERLOAD
verse-time delayed trip; a flickering red light signals an immi-
nent inverse-time delayed trip (overload warning).
Overload Relays
3RB2 Solid-State Overload Relays
3RB22, 3RB23 for high-feature applications
Auxiliary contacts
The 3RB22/3RB23 solid-state overload relays have two outputs,
each with one NO contact and one NC contact. Their basic as-
signment/function may be influenced by function expansion mo-
dules.
The 3RB22 and 3RB23 differ with respect to the tripping charac-
teristics of their auxiliary contacts – monostable or bistable:
The monostable 3RB22 solid-state overload relays will enter the
"tripped" state if the control voltage fails (> 200 ms), and return
to the original state they were in before the control supply vol-
tage failed when the voltage returns. These devices are there-
fore especially suited for plants in which the control voltage is not
strictly monitored.
The bistable 3RB23 overload relays do not change their "tripped"
or "not tripped" status if the control voltage fails. The auxiliary
contacts only switch over in the event of an overload and if the
supply voltage is present. These devices are therefore espe-
cially suited for plants in which the control voltage is monitored
separately.
Response if the control supply voltage fails
If the control supply voltage fails for more than 0.2 s, the output
relays respond differently depending on the version: monostable
or bistable.
Response of the
Monostable
output relays
3RB22
in the event of
Failure of the control
The device trips
supply voltage
Return of the control
The device resets
supply voltage wit-
hout previous trip-
ping
Return of the control
The device remains trip-
supply voltage after
ped
previous tripping
Reset:
• For overload tripping,
after 3 minutes
• For thermistor tripping,
after the temperature
has fallen 5 K below the
response temperature
• For ground-fault trip-
ping, immediately
Monostable and bistable responses of the output relays
Control
1
0
supply
voltage
NO
monostable
NC
NO
bistable
NC
NO
monostable
NC
NO
bistable
NC
M o t o r t e m p .
t o o h i g h ;
d e v i c e t r i p s
C o n t a c t o r o p e n
C o n t a c t o r c l o s e d
Bistable
3RB23
No change of the swit-
ching state of the auxiliary
contacts
No change of the swit-
ching state of the auxiliary
contacts
The device remains trip-
ped
Reset:
• For overload tripping,
after 3 minutes
• For thermistor tripping,
after the temperature
has fallen 5 K below the
response temperature
• For ground-fault trip-
ping, immediately
t
NSB0_01628
C o n t r o l
R e t u r n o f
M a n u a l / a u t o r e s e t
c o n t r o l
s u p p l y
a f t e r 3 m i n
v o l t a g e
s u p p l y
o r a f t e r t h e r m i s t o r
v o l t a g e
f a i l u r e
h a s c o o l e d d o w n
Siemens · 2011
31
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