ABB RED615 Technical Manual page 529

1YHT530004D05 D
615 series
Technical Manual
When the measured current value is used for startup supervision in the "IIt" and "IIt
& stall" modes, the module initially recognizes the de-energized condition of the
motor when the values of all three phase currents are less than Motor standstill A
for longer than 100 milliseconds. If any of the phase currents of the de-energized
condition rises to a value equal to or greater than Motor standstill A, the
MOT_START output signal is activated indicating that the motor startup is in
progress. The MOT_START output remains active until the values of all three phase
currents drop below 90 percent of the set value of Start detection A and remain
below that level for a time of Str over delay time, that is, until the startup situation
is over.
GUID-4475BDFB-57AE-4BFD-9EE7-AE7672F7206E V2 EN
Figure 274: Functionality of startup supervision in the "IIt and IIt&stall" mode
In case of the "IIt, CB" or "IIt & stall, CB" modes, the function initially recognizes
the de-energized condition of the motor when the value of all three phase currents
is below the value of the Motor standstill A setting for 100 milliseconds. The
beginning of the motor startup is recognized when CB is closed, that is, when the
CB_CLOSED input is activated and at least one phase current value exceeds the
Motor standstill A setting.
These two events do not take place at the same instant, that is, the CB main contact
is closed first, in which case the phase current value rises above 0.1 pu and after
some delay the CB auxiliary contact gives the information of the CB_CLOSED
input. In some cases, the CB_CLOSED input can be active but the value of current
may not be greater than the value of the Motor standstill A setting. To allow both
possibilities, a time slot of 200 milliseconds is provided for current and the
CB_CLOSED input. If both events occur during this time, the motor startup is
recognized.
The motor startup ends either within the value of the Str over delay time setting
from the beginning of the startup or the opening of CB or when the CB_CLOSED
Section 4
Protection functions
523