Danfoss VLT AutomationDrive FC 300 Design Manual page 51

FC 300 Design Guide
Activate the Safe Stop function by removing the 24 V DC voltage supply to the terminal 37.
1.
After activation of Safe Stop, the frequency converter coasts (stops creating a rotational field in the motor).
2.
The frequency converter is guaranteed not to restart creation of a rotational field by an
internal fault (in accordance with Cat. 3 of EN 954-1).
After activation of Safe Stop, the FC 302 display will show the text "Safe Stop activated". The associated
help text says "Safe Stop has been activated. This means that the Safe Stop has been activated, or that
normal operation has not been resumed yet after Safe Stop activation. NB: The requirements of EN 945-1
Category 3 are only fulfilled while 24 V DC supply to terminal 37 is removed or low.
In order to resume operation after activation of Safe Stop, first 24 V DC voltage must be
reapplied to terminal 37 (text "Safe Stop activated" is still displayed), second a Reset signal
must be created (via bus, Digital I/O, or [Reset] key on inverter).
NB!:
The Safe Stop function of FC 302 can be used for asynchronous and synchronous motors. It
may happen that two faults occur in the frequency converter's power semiconductor. When
using synchronous motors this may cause a residual rotation. The rotation can be calculated to
Angle=360/(Number of Poles). The application using synchronous motors must take this into consideration
and ensure that this is not a safety critical issue. This situation is not relevant for asynchronous motors.
NB!:
In order to use the Safe Stop functionality in conformance with the requirements of
EN-954-1 Category 3, a number of conditions must be fulfilled by the installation of Safe
Stop. Please see section Safe Stop Installation for further information.
NB!:
The frequency converter does not provide a safety-related protection against unintended or
malicious voltage supply to terminal 37 and subsequent reset. Provide this protection via
the interrupt device, at the application level, or organisational level.
For more information - see section Safe Stop Installation.
Introduction to FC 300
MG.33.B4.02 - VLT is a registered Danfoss trademark
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