Table 28. Thermal overload protection, one time constant LPTTR (26)
Function
Range or value
Accuracy
Reference current
(0-400)% of
IBase
±
1.0% of I
n
Reference temperature
(0-600)°C
±
1.0°C
Operate time:
2
2
2
2
ln
p
b
I
I
t
I
I
t
æ
ö
-
ç
÷
= ×
ç
÷
-
è
ø
EQUATION1356 V1 EN
(Equation 1)
I = actual measured
current
I
p
= load current before
overload occurs
I
b
= base current, IBase
Time constant
t
= (0–
1000) minutes
IEC 60255-8, class 5 + 200 ms
Alarm temperature
(0-200)°C
±
2.0% of heat content trip
Trip temperature
(0-600)°C
±
2.0% of heat content trip
Reset level temperature
(0-600)°C
±
2.0% of heat content trip
Breaker protection REQ650 ANSI
1MRK 505 269-BUS -
Product version: 1.1
Issued: April 2011
ABB
61