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JKSSS+ Series - 8
JKSSS+ Series 2.3 - 4.2KV
1.6 General Protection
The soft starter is provided with a built-in motor protection relay that can be
programmed for primary protection of the motor/load system. Operation of the soft
starter can be divided into 4 modes; Ready, Start, Run and Stop.
Ready Mode: In this mode, control and line power are applied and the starter is
ready for a start command. Protection during this mode includes the monitoring
of current for leakage through multiple shorted SCRs or welded contacts on the
Bypass Contactor. Other protection features in effect are:
· Starter Temperature
· Shorted SCR
· Phase Reversal (if enabled)
· Line Frequency Trip Window
· External Input Faults
Note: The “Programming Mode” can only be entered from the Ready Mode.
During programming, all protection features and start command are disabled.
Start Mode: These additional protection functions are enabled when the soft
starter receives a valid Start command:
· Phase Reversal (if enabled)
· Start Curve
· Acceleration Timer
· Phase Imbalance
· Short Circuit / Load Pre-check (Toe-in-the-Water)
· Ground Fault (Optional)
· External Input Faults
· Accumulated Starting FLA Units (I
2
t Protection)
· Overload Protection
· Thermal Capacity
Note: Shorted SCR and Shunt Trip protection are no longer in effect once the
soft starter goes into the Start Mode.
Run Mode: The soft starter enters the Run Mode when it reaches full output
voltage and the motor current drops below the FLA setting (motor nameplate
FLA plus service factor) for a predetermined period of time. During the Run Mode
these additional protection features are enabled:
· Running Overload Curve
· Phase Loss
· Under Current / Load Loss
· Over Current / Electronic Shear Pin (Jam protection)
· External Input Faults
Stop Mode: Once a Stop command has been given, the protection features
change depending on which Stop Mode is selected.
· Decel Mode: Retains all protection features of the Run Mode. At the end of
Decel, the motor will be stopped and the protection features change as
indicated below.