Terminals PIN14 and PIN15 can be used for other functions depending on the invertir bridge
characteristics (frequency regulation by external potentiometer, analogue feedback, etc.). to avoid
multiple connections in one terminal (PIN 14, PIN 15), it is advisable to add external terminals for
supply distribution.
STO - Safe Torque Off
The STO function is defined as: Power, that can cause rotation, is not applied to the motor. The frequency
converter will not provide energy to the motor, which can generate torque.
For three-phase asynchronous motor, that means to stop three-phase power supply to the stator.
This function corresponds to a Category 0 Emergency Stop according to IEC 60204-1. When the drive
is running and the STO function is applied, the motor will freely stop by its own inertia.
The STO function integrated as standard in the SD750 permits to achieve safety level SIL3 (PLe) for the
safe stop function. SIL3 requires the use of an emergency pushbutton The maximum reaction time of
STO function is less than 50ms. See section “Safety Integrity Level SIL3-PLe” for additional information.
By using this function you can safely carry out cleaning, maintenance or emergency work on non-electric
parts of the equipment, without having to disconnect the power supply. In case STO safety function is
not used, user must connect the corresponding terminals.
Based on a study of each application and risk assessment, the designer should define the required safety
function and safety level.
CAUTION
The STO safety function does not disconnect nor the main neither the auxiliary power supply.
With STO function the drive disconnects the motor power supply. To carry out electrical
maintenance tasks, isolate the inverter. Particular care must be taken with the active conductors
inside the inverter. Failure to do so could result in damage to equipment and personnel.
To Next Page
Loading...
Need help?
General
