Safe Stop Operation (Optional) - Danfoss VLT AQUA Drive FC 202 Design Manual

Introduction
Input Supply Voltage V
Digital/analog Cut-out Values
Digital 24
Digital 10
Analog 10
NOTE
Check that the chosen supply voltage follows the specifi-
cation of the used thermistor element.
Summary
With the torque limit feature, the motor is protected from
being overloaded independent of the speed. With the ETR
the motor is protected for being over heated and there is
no need for any further motor protection. That means
when the motor is heated up the ETR timer controls for
how long time the motor can be running at the high
temperature before it is stopped in order to prevent over
heating. If the motor is overloaded without reaching the
temperature where the ETR shuts off the motor, the torque
limit is protecting the motor and application for being
overloaded.
ETR is activated in 1-90 Motor Thermal Protection and is
controlled in 4-16 Torque Limit Motor Mode. The time
before the torque limit warning trips the frequency
converter is set in 14-25 Trip Delay at Torque Limit.

2.15.2 Safe Stop Operation (optional)

The FC 202 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.
Before integration and use of FC 202 safe stop in an instal-
lation, a thorough risk analysis on the installation must be
carried out in order to determine whether the FC 202 safe
stop functionality and safety category are appropriate and
sufficient.
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
relay, an installation for a safe stop category 1 can be
obtained. The safe stop function of FC 202 can be used for
asynchronous and synchronous motors.
WARNING
Safe Stop activation (that is, removal of 24 V DC voltage
supply to terminal 37) does not provide electrical safety.
®
VLT AQUA Drive FC 202 Design Guide
Threshold
Cut-out Values
< 6.6kΩ - > 10.8kΩ
< 800Ω - > 2.7kΩ
< 3.0kΩ - > 3.0kΩ
®
MG20Z102 - VLT is a registered Danfoss trademark
NOTE
The safe stop function of FC 202 can be used for
asynchronous and synchronous motors. Two faults can
occur in the power semiconductor and cause a residual
rotation when using synchronous motors. The rotation can
be calculated to Angle=360/(Number of Poles). The
application using synchronous motors must consider this
possibility and ensure that it 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, the instal-
lation of safe stop must meet a number of conditions. See
5.7 Safe Stop Installation for further information.
NOTE
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 5.7 Safe Stop Installation.
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