Danfoss VLT AQUA Drive FC 200 Programming Manual page 9

Introduction
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not sufficient. In such cases the mains supply
must be disconnected or the Safe Stop function
must be activated.
2. The motor may start while setting the
parameters. If this means that personal safety
may be compromised (e.g. personal injury caused
by contact with moving machine parts), motor
starting must be prevented, for instance by use
of the Safe Stop function or secure disconnection
of the motor connection.
3. A motor that has been stopped with the mains
supply connected, may start if faults occur in the
electronics of the frequency converter, through
temporary overload or if a fault in the power
supply grid or motor connection is remedied. If
unintended start must be prevented for personal
safety reasons (e.g. risk of injury caused by
contact with moving machine parts), the normal
stop functions of the frequency converter are not
sufficient. In such cases the mains supply must be
disconnected or the Safe Stop function must be
activated.
NOTE
When using the Safe Stop function, always follow the
instructions in the section Safe Stop of the VLT
Drive Design Guide, MG20N.
4. Control signals from, or internally within, the
frequency converter may in rare cases be
activated in error, be delayed or fail to occur
entirely. When used in situations where safety is
critical.
WARNING
High Voltage
Touching the electrical parts may be fatal - even after the
equipment has been disconnected from mains.
Also make sure that other voltage inputs have been
disconnected, such as external 24 V DC, load sharing
(linkage of DC intermediate circuit), as well as the motor
connection for kinetic back up.
Systems where frequency converters are installed must, if
necessary, be equipped with additional monitoring and
protective devices according to the valid safety regulations,
e.g law on mechanical tools, regulations for the prevention
of accidents etc. Modifiying the frequency converters with
the operating software is allowed.
8
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VLT AQUA Drive Programming Guide
NOTE
Hazardous situations shall be identified by the machine
builder/integrator who is responsible for taking necessary
preventive means into consideration. Additional
monitoring and protective devices may be included, always
according to valid national safety regulations, e.g. law on
mechanical tools, regulations for the prevention of
accidents.
Protection Mode
Once a hardware limit on motor current or DC link voltage
is exceeded the frequency converter will enter "Protection
mode". "Protection mode" is a change of the PWM
modulation strategy and a low switching frequency to
minimize losses. This continues 10 s after the last fault and
increases the reliability and the robustness of the
frequency converter while re-establishing full control of the
motor.
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AQUA
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MG20O602 - VLT is a registered Danfoss trademark