Siemens SINAMICS G220 - Stop Functions; Safe Torque off (STO)

14.12.4 Stop functions
14.12.4.1 Safe Torque O󹪜 (STO)
Overview
450
W
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Figure14-224 Overview STO
The Safe Torque O󹪜 (STO) function prevents the torque-generating supply of energy to the
motor and prevents the motor from unexpectedly starting.
Requirement
STO is enabled in the function selection.
WARNING
Unexpected motor movement through active Safe Torque O󹪜
There may be unexpected motor movements if the Safe Torque O󹪜 (STO) function is active. For
instance, the motor can coast down to a standstill or a hanging load may accelerate the motor.
Unexpected movements can lead to damage to property, risk to persons, severe injury and
death.
• Take account of the way the Safe Torque O󹪜 (STO) function works when you perform risk
assessments of the machine or system.
• Prevent movements of the motor, for example by using a holding brake.
WARNING
Danger due to short, limited motion
If two power transistors simultaneously fail in the power unit (one in the upper and one in the
lower inverter bridge), then this can cause brief, limited movement.
The maximum movement can be:
• Synchronous rotary motors: Max. movement = 180° / no. of pole pairs
• Synchronous linear motors: Max. movement = pole width
Functions
14.12Safety Integrated
SINAMICS G220 converter
Operating Instructions, 04/2024, FW V6.2, A5E51781573B AB 659