Coasting Down; Coasting Down (Page 148) - Siemens SIRIUS 3RW55 Equipment Manual

Functions
8.2 Run-down
Speed curve
①
②
③
t
1
8.2.2

Coasting down

Operating principle
Coasting down means the power supplied to the motor via the 3RW55 or 3RW55 Failsafe soft
starter is interrupted when the ON command is removed from the 3RW55 or 3RW55 Failsafe soft
starter. The motor will coast down freely without closed-loop control, driven only by the mass
inertia (centrifugal mass) of the rotor and load. This is also referred to as natural stopping. A
larger centrifugal mass means a longer stop time without load.
Coasting down is used for loads that make no special demand on the startup characteristic.
Application
• E.g. fan
Setting via 3RW5 HMI High Feature
• Menu: "Parameters > Soft Starter > Parameter set 1 / 2 / 3 > Stopping mode settings >
Stopping mode > Coasting down"
• Access protection to the 3RW5 HMI High Feature is not active or has been reset.
148
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DC braking
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Coasting down
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Torque controlled stopping
Stop command on the 3RW55 or 3RW55 Failsafe soft starter
SIRIUS 3RW55 and 3RW55 Failsafe Soft Starters
Equipment Manual, 02/2022, A5E35630887002A/RS-AF/006