Cutler Hammer, Div of Eaton Corp S811 Operation Diagram

Reduced Voltage Motor Starters

Run (FLA)

100%

Locked Rotor Torque

Time (Seconds)

Initial

Torque

Run

Max.

Allowed

100%

FLA

Current

Time (Seconds)

1.2

Operation

1

Starting and Stopping Modes

1

The S811 has a variety of starting and stopping methods to provide superior performance in the
most demanding applications. The motor can be started in either voltage ramp start or current
limit start mode. Kick start and soft stop are available within both starting modes.

1

Voltage Ramp Start

1

Provides a voltage ramp to the
motor resulting in a constant

1

torque increase. The most
commonly used form of soft

1

start, this start mode allows
you to set the initial torque
value and the duration of the

1

ramp to full voltage
conditions. Bypass contactors

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close after ramp time.

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Starting Characteristics—Ramp Start

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Solid-State Starters

●

Adjustable initial torque
0–85% of locked rotor
torque

●

Adjustable ramp time

0.5–180 seconds (can be
extended with factory
modification)

1

1

1

1

1

Current Limit Start

Limits the maximum current

1

available to the motor during
the start phase. This mode of
soft starting is used when it

1

becomes necessary to limit
the maximum starting current

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due to long start times or to
protect the motor. This start

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Starting Characteristics—Current Limit Start

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1

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mode allows you to set the
maximum starting current as a
percentage of locked rotor
current and the duration of the
current limit. Bypass
contactors close after current
limit time.

●

Maximum current of
0–85% locked rotor current

●

Adjustable ramp time

0.5–180 seconds (can be
extended with factory
modification)

1

1

1

1

1

Reduced Voltage Motor Starters

100%

Locked Rotor Torque

Ramp

Time (Seconds)

Kick

Start

Run (FLA)

Ramp

Time (Seconds)

Run

Solid-State Starters

1.2

Kick Start

Selectable feature in both
voltage ramp start and
current limit start modes.
Provides a current and torque
“kick” for 0 to 2.0 seconds.
This provides greater initial
current to develop additional
torque to breakaway a high
friction load.

Starting Characteristics—Kick Start

●

●

0–85% of locked rotor
torque

0–2.0 seconds duration

1

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Soft Stop

Allows for a controlled
stopping of a load. Used
when a stop-time that is
greater than the coast-to-stop
time is desired. Often used
with high friction loads where
a sudden stop may cause
system or load damage.

Starting Characteristics—Soft Stop

●

Stop time = 0–60 seconds

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