ABB RED615 Technical Manual page 255

1YHT530004D05 D
615 series
Technical Manual
Env temperature mode setting is on "Use input" mode, the internal FLC is
calculated from temperature data available through resistance temperature detectors
(RTDs) using the AMB_TEMP input.
Table 256: Modification of internal FLC
Ambient Temperature T
amb
<20°C
20 to <40°C
40°C
>40 to 65°C
>65°C
The ambient temperature is used for calculating thermal level and it is available in
the monitored data view from the TEMP_AMB output. The activation of the BLOCK
input does not affect the TEMP_AMB output.
The Env temperature Set setting is used:
• If the ambient temperature measurement value is not connected to the
AMB_TEMP input in ACT.
• When the ambient temperature measurement connected to 49M is set to Not in
use in the RTD function.
• In case of any errors or malfunctioning in the RTD output.
Thermal level calculator
The module calculates the thermal load considering the TRMS and negative-
sequence currents. The heating up of the motor is determined by the square value
of the load current.
However, in case of unbalanced phase currents, the negative-sequence current also
causes additional heating. By deploying a protection based on both current
components, abnormal heating of the motor is avoided.
The thermal load is calculated based on different situations or operations and it also
depends on the phase current level. The equations used for the heating calculations
are:
2

  
I

=  + K ×
θ
 
B 2
 k I × k I
  
r

GUID-526B455A-67DD-46E7-813D-A64EC619F6D7 V2 EN
2

  
I

=  + ×
K
θ
 
A 2
 k I × k I
  
r

GUID-9C893D3E-7CAF-4EA6-B92D-C914288D7CFC V2 EN
Internal FLC
FLC x 1.09
FLC x (1.18 - T
FLC
FLC x (1 –[(T
FLC x 0.75
2


I
( )
− t /
2
τ

× − e × p
1 %

× 

r

2


I
( )
− t /
2
τ

× − 1 × 100 %
e

× 

r

Section 4
Protection functions
x 0.09/20)
amb
-40)/100])
amb
(Equation 10)
(Equation 11)
249