Eaton S611 - Current Limit Start; Soft Stop;Pump Stop

S611 Soft Starter MN03902011E—May 2012 www.eaton.com 19
Current Limit Start
This mode is typically used when it is necessary to limit the maximum current during start-up
due to line power limitations or other considerations. During a current limit start the S611
applies a constant voltage to the motor, resulting in limited current flowing through the
motor’s windings. The level of current is set by the Initial Torque parameter. (See figure
below.)
Note: Current limit starts are not recommended on variable torque load applications like fans
and pumps. Attempting starts with the current limit set to a value of 20% initial torque
or lower are not recommended.
Current Limit
Soft Stop/Pump Stop—This feature is used for applications that require a controlled
extended stop. It is designed for high frictional loads that tend to stop suddenly or to prevent
water hammer (pumps) when voltage to the motor is removed. During soft stop, the voltage
is gradually reduced to zero in the time set by the Soft Stop Time parameter. (See figure
below.)
Note: The soft stop mode is not an electronic brake function and will not stop a motor any
faster than it would normally take to coast to a stop under load.
Soft Stop
Initial
Torque
Kick
Start
Torq
Kick Start Time
100%
Bypass Bypass
Soft Start Time
Start Run
Current
Time (Seconds) Time (Seconds)
100%
Start Run
Speed
Soft
Stop Time
100%
Run Soft Stop
Speed
Time (Seconds)
Coast to Stop
(Speed)
Soft Stop Ramp
(Voltage)
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