Safe Stop Of Fc 300 - Danfoss FC 300 Design Manual

FC 300 Design Guide

Safe Stop of FC 300

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The adjustable frequency drive can perform the Safety Function "Uncontrolled Stopping by removal of
power" (as defined by draft IEC 61800-5-2) or Stop Category 0 (as defined in EN 60204-1).
It is designed and approved suitable for the requirements of Safety Category 3 in EN
954-1. This functionality is called Safe Stop.
The Safe Stop function is activated by removing the voltage at Terminal 37 of the Safe Inverter. By connecting
the Safe Inverter to external safety devices providing a safe delay, an installation for a safe Stop Category
1 can be obtained. The safe inverter can be used for asynchronous and synchronous motors.
Safe Stop activation (i.e. removal of 24 V DC voltage supply to terminal 37)
does not provide electrical safety.
Activate the Safe Stop function by removing the 24 V DC voltage supply to the terminal 37.
1.
2. After activation of Safe Stop, the adjustable frequency drive coasts (stops creating a rotational
field in the motor). The resonse time is shorter than 10 ms for the complete performance range
of FC 302. For FC 302 up to 7.5 kW it is even shorter than 5 ms.
The adjustable frequency drive 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 active". The associated
help text says "Safe Stop has been activated. To resume normal operation, apply 24 V DC to terminal
37, then send Reset signal (via Bus, Digital I/O, or the [Reset] key)." This means that the Safe Stop has
been activated, or that normal operation has not been resumed yet after a 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 active" is still displayed), second a Reset signal must
be created (via bus, Digital I/O, or [Reset] key on inverter).
NOTE
The Safe Stop function of FC 302 can be used for asynchronous and synchronous motors. It
may happen that two faults occur in the adjustable frequency drive'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.
NOTE
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.
NOTE
The adjustable frequency drive 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 at the organizational level.
For more information - see section Safe Stop Installation.
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Introduction to FC 300
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