ABB RET 541 Product Manual page 27

Transformer Terminal
Three-phase thermal overload protection for motors, generators and transformers, TOL3Dev, 3
BASIC SETTINGS:
Starting current of the motor
Max. starting time permitted for the motor
Number of starts allowed from cold state
Type of device to be protected
Trip temperature
Prior alarm temperature
Restart inhibit (temperature limit for
successful restarting)
Ambient temperature
Cooling time-constant
Heating time-constant for generator or
transformer
ADVANCED SETTINGS:
Short time-constant for stator
Long time-constant for stator
Weighting factor of the short time-constant for
stator
Temperature rise of stator at rated current
Maximum temperature of stator
Short time-constant for rotor
Long time-constant for rotor
Weighting factor of the short time-constant for
rotor
Temperature rise of rotor at rated current
Maximum temperature of rotor
Operation mode (principle of ambient
temperature compensation)
Waiting time for a successful restart (Read-
only parameter)
Estimated time to the trip (Read-only
parameter)
Operation accuracy
Reset ratio:
- trip
- start
- restart
RET 541, RET 543, RET 545
0.10...10.00 x In
0.1...120.0 s
1...3
Motor; through-ventilated, rated power < 1500 kW
Motor; through-ventilated, rated power > 1500 kW
Motor; surface cooling, rated power < 500 kW
Motor; surface cooling, rated power > 500 kW
Generator; hydro or small air-cooled turbine generators
Generator; large turbine generators
Transformer
80.0...120.0%
40.0...100.0%
40.0...100.0%
-50.0...100.0C
1.0...10.0 x time constant
1...999 min
0.0...999.0 min
0.0...999.0 min
0.00...1.00
0.0...350.0 C
0.0...350.0 C
0.0...999.0 min
0.0...999.0 min
0.00...1.00
0.0...350.0 C
0.0...350.0 C
Not in use
No sensors; the set ambient temperature
1 sensor used
2 sensors used
0...86400 s
0...86400 s
Note! The values below apply when f/fn = 0.95...1.05
±1.0%, I = 0.1...10.0 x In
(Calculated temp. rise - 0.1) / Trip temperature
(Calculated temp. rise - 0.1) / Prior alarm temperature
(Calculated temp. rise - 0.1) / Restart inhibit temperature
limit
1MRS755543
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