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11.2.5
Features of overload relays
Table 11- 5
Other characteristics of 3RU21 and 3RB30/3RB31 overload relays
Feature
Temperature compensation
High long-term stability
Wide setting ranges
Tripping class CLASS 5E
Tripping class > CLASS 10E
Low power loss
Intrinsic supply
Variable setting of tripping
classes
(The required tripping class can
be set dependent upon the
prevailing starting conditions
using a rotary switch.)
As SIRIUS 3RU21 thermal overload relays work on the basis of the bimetal principle, they
1)
do not require a control supply voltage.
SIRIUS Innovations - SIRIUS 3RU2 thermal overload relays / SIRIUS 3RB3 solid-state overload relays
Manual, 09/2014, A5E03656507420A/RS-AA/002
Description
Allows the use of the relays without derating even
•
at high temperatures
Prevents premature tripping
•
Allows compact control cabinet installation without
•
clearance between the devices/load feeders
Simplifies configuration
•
Enables space to be saved in the control cabinet
•
Provides reliable protection of loads even after
•
years under severe operating conditions
Reduce the number of variants
•
Minimize the engineering outlay and costs
•
Enable savings to be made where storage
•
overheads, storage costs, and tied-up capital are
concerned
Enables solutions for motors which start up very
•
quickly and require special protection measures
Enable solutions for heavy-duty starting
•
Reduces power consumption (power consumption
•
is up to 98% less than with thermal overload relays)
and thus energy costs
Minimizes the temperature rise of the contactor and
•
the control cabinet - in some cases this may
eliminate the need for control cabinet cooling
Enables space to be saved through direct mounting
•
on the contactor even at high motor currents (i.e.
no heat decoupling is required)
Eliminates the need for configuration and
•
connecting an additional control circuit
Reduces the number of variants
•
Minimizes the engineering outlay and costs
•
Enables savings to be made where storage
•
overheads, storage costs, and tied-up capital are
concerned
Technical data
11.2 Performance features
3RU21
3RB30/3RB31
✓
✓
✓
✓
--
✓
(1:4)
--
✓
(3RB31 only)
--
✓
--
✓
--
✓
1)
--
✓
(3RB31 only)
107
- Quick Links:
- 3Ru21 Thermal Overload Relays
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