Table 54. Thermal overload protection, one time constant LCPTTR/LFPTTR
Function Range or value Accuracy
Reference current (2-400)% of IBase ±1.0% of I
r
Reference temperature (0-300)°C, (0 - 600)°F
±1.0°C, ±2.0°F
Operate time:
2 2
2 2 2
ln
p
Trip Amb
p ref
ref
I I
t
T T
I I I
T
t
-
=
-
- - ×
é ù
ê ú
ê ú
ê ú
ê ú
ë û
EQUATION13000039 V2 EN (Equation 1)
T
Trip
= set operate temperature
T
Amb
= ambient temperature
T
ref
= temperature rise above ambient at I
ref
I
ref
= reference load current
I = actual measured current
I
p
= load current before overload occurs
Time constant t = (1–1000)
minutes
IEC 60255-8, ±5.0% or ±200 ms whichever is greater
Alarm temperature (0-200)°C, (0-400)°F ±2.0°C, ±4.0°F
Operate temperature (0-300)°C, (0-600)°F ±2.0°C, ±4.0°F
Reset level temperature (0-300)°C, (0-600)°F ±2.0°C, ±4.0°F
Table 55. Breaker failure protection CCRBRF
Function
Range or value Accuracy
Operate phase current (5-200)% of
lBase
±1.0% of I
r
at I £ I
r
±1.0% of I at I > I
r
Reset ratio, phase current > 95% -
Operate residual current (2-200)% of
lBase
±1.0% of I
r
at I £ I
r
±1.0% of I at I > I
r
Reset ratio, residual current > 95% -
Phase current level for blocking of contact function (5-200)% of
lBase
±1.0% of I
r
at I £ I
r
±1.0% of I at I > I
r
Reset ratio > 95% -
Operate time for current detection 20 ms typically -
Reset time for current detection 25 ms maximum -
Time delay for re-trip at 0 to 2 x I
set
(0.000-60.000) s ±0.2% or ±30 ms whichever is
greater
Time delay for back-up trip at 0 to 2 x I
set
(0.000-60.000) s ±0.2% or ±30 ms whichever is
greater
Time delay for back-up trip at multi-phase start at 0 to 2 x I
set
(0.000-60.000) s ±0.2% or ±35 ms whichever is
greater
Additional time delay for a second back-up trip at 0 to 2 x I
set
(0.000-60.000) s ±0.2% or ±35 ms whichever is
greater
Time delay for alarm for faulty circuit breaker (0.000-60.000) s ±0.2% or ±30 ms whichever is
greater
1MRK 505 346-BEN -
Line differential protection RED670 2.1 IEC
Product version: 2.1
72 ABB