ABB REG650 Technical Manual page 187

1MRK 502 034-UEN -
Technical Manual
After a trip, caused by the thermal overload protection, there can be a lockout to
reconnect the tripped circuit. The output lockout signal LOCKOUT is activated
when the temperature of the object is above the set lockout release temperature
setting ResLo.
The time to lockout release is calculated, That is, a calculation of the cooling time
to a set value.
æ
t
= - × ç
t ln
ç
lockout release _
è
EQUATION1177 V1 EN
In the above equation, the final temperature is calculated according to equation 45.
Since the transformer normally is disconnected, the current I is zero and thereby
the Θ is also zero. The calculated component temperature can be monitored as it
final
is exported from the function as a real figure, TRESLO.
When the current is so high that it has given a start signal START, the estimated
time to trip is continuously calculated and given as analogue output TTRIP. If this
calculated time get less than the setting time Warning, set in minutes, the output
WARNING is activated.
ö
Q - Q
final lockout release _
÷
÷
Q - Q
ø
final n
Section 7
Current protection
(Equation 51)
181