Introduction
S811+ Soft Starter MN03900001E—November 2012 1
Introduction
Overview
The Eaton S811+ Soft Starter from Eaton’s electrical 
business is an electronic, self-contained, panel- or 
enclosure-mounted motor soft-starting device. It is intended 
to provide three-phase induction motors with a smooth start, 
both mechanically and electrically. The S811+ Soft Starters 
utilize six SCRs connected in a full wave power bridge. 
Varying the SCR conduction period controls the voltage 
applied to the motor. This in turn controls the torque 
developed by the motor. After the motor reaches speed, 
internal contacts are closed to bypass the SCRs.
The S811+ has built-in communications capabilities via a 
Communications Port. The Communications Port is a screw 
terminal block that is utilized for ModBus
®
 communications 
or communication to an EATON HMI. Communications 
adapters are available for other protocols. Please consult 
Eaton for availability. 
The S811+ Soft Starter utilizes a Digital Interface Module 
(DIM) that allows the user to configure the device, read and 
write system parameters, and evaluate fault codes for 
troubleshooting. 
The DIM includes an easy-to-read display and keypad to 
scroll through the parameters. The Digital Interface Module 
allows the user to modify control parameters, enable or 
disable protections, set system variances from Fault TRIP to 
Fault WARNING, set communication variables, monitor 
system parameters such as line voltages and currents and 
access the fault queue.
The S811+ is designed to fulfill the industrial service 
requirements for applications such as Chillers, Pumps and 
Machine Tools that require less than 100% of the motor’s 
rated starting torque for worst case starting condition.
The S811+ meets all relevant specifications set forth 
by UL 508, CSA 22.2-14-1995 IEC 60947-4-2, and 
CCC GB14048.
General Appearance Notes
Eaton S811+ Soft Starter