S611 Soft Starter MN03902011E—May 2012 www.eaton.com 55
Over Voltage
The S611 monitors the maximum rms voltage and checks the value just prior to starting to
determine if a fault shall be issued and the start will be terminated. When the bypass
contactors are engaged, the S611 monitors the maximum rms voltage and issues a over
voltage fault if the measured value exceeds the threshold for the trip delay time. Note that the
S611 will not generate an over voltage fault when the motor is starting.
Over Voltage Settings
Device Current Protection
The S611 has a number of protection mechanisms that cannot be disabled by the customer.
These are to protect both the motor and the starter itself.
Device Current Protection Values
SCR Not Firing (SCR Not Conducting)
The S611 has detection for SCRs not firing. This typically catches broken wires to the SCRs,
disconnected cables, nonfunctioning SCRs, and firing circuit failure. This also captures Open
SCR condition. The firmware monitors the number of current stops detected after firing. If no
current stops are detected on a phase for a number of cycles, then the SCR not firing fault is
issued.
Shorted SCR
The S611 has detection for shorted SCRs. The shorted SCR fault is triggered if the S611
detects current flowing when the motor is off or if the BEMF pulses for a phase disappear
and the voltage across the SCR is near 0 (not exactly 0 due to noise considerations) when a
start is commanded.
The soft starter has several different modes of current and voltage protection to help protect
the motor and the starter itself. Depending on how the device is set up, different levels of
protection can be attained.
Parameter Set Point Range Step Default Notes
Trip threshold OFF, 101–120%
rated voltage
1% 110% Settable from the UI
Mode O/P LED
Protection Under voltage %
Trip delay 1–60 seconds 1 10 seconds Settable from the UI
Mode O/P LED
Operation Advanced Conf—P.21
Type Trip Threshold
Time Before Trip
(Seconds)
When in Effect
SCR inrush current 6x (Cat# FLA) <1.5 Always, when not in bypass
SCR overcurrent 3x (FLA) At end of ramp Stall disabled, on SCRs
Contactor overcurrent 4x (Cat# FLA) 4.5 seconds
9.0 seconds
16.0 seconds
23.0 seconds
• Jam DIP switch and in bypass
• Note these have been
modified from S811 based on
contactor evaluation
Pole over temperature >100°C 1 second Always
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