ABB REC650 - Monitored Data; Operation Principle

6.6.6 Monitored data
Table 63: LCPTTR Monitored data
Name
Type Values (Range) Unit Description
TTRIP INTEGER - - Estimated time to trip (in
min)
TENRECL INTEGER - - Estimated time to reset of
lockout (in min)
TEMP REAL - deg Calculated temperature
of the device
TEMPAMB REAL - deg Ambient temperature
used in the calculations
Table 64: LFPTTR Monitored data
Name Type Values (Range) Unit Description
TTRIP INTEGER - - Estimated time to trip (in
min)
TENRECL INTEGER - - Estimated time to reset of
lockout (in min)
TEMP REAL - Temperature
Fahrenheit
Calculated temperature
of the device
TEMPAMB REAL - Temperature
Fahrenheit
Ambient temperature
used in the calculations
6.6.7 Operation principle
The sampled analog phase currents are pre-processed and for each phase current the
RMS value is derived. These phase current values are fed to the thermal overload
protection, one time constant LCPTTR/LFPTTR function. The temperature is
displayed either in Celsius or Fahrenheit, depending on whether LCPTTR/LFPTTR
function is selected.
From the largest of the three-phase currents a final temperature is calculated according
to the expression:
2
final ref
ref
I
T
I
æ ö
Q = ×
ç ÷
ç ÷
è ø
EQUATION1167 V1 EN (Equation 16)
where:
I is the largest phase current,
I
ref
is a given reference current and
T
ref
is steady state temperature rise corresponding to I
ref
1MRK 511 287-UEN A Section 6
Current protection
125
Technical manual