ABB RELION 620 Series Technical Manual page 765

1MRS757644 F
620 series
Technical Manual
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 start-up is recognized.
The motor start-up ends either within the value of the Str over delay time setting from
the beginning of the start-up or the opening of CB or when the CB_CLOSED input is
deactivated. The operation of the MOT_START output signal in this operation mode
is as illustrated in Figure
This CB mode can be used in soft-started or slip ring motors for protection against a
large starting current, that is, a problem in starting and so on.
GUID-DDAD7B3F-28BE-4573-BE79-FBB488A22ECA V1 EN
GUID-1470A4DB-310F-46BC-B775-843EAB8BA836 V1 EN
Figure 389: Functionality of start-up supervision in the "IIt, CB" mode and the "IIt
and stall, CB" mode
389.
Section 4
Protection functions
759