GD200A series VFD Installation guidelines
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4.4.2 Protecting the motor and motor cable in short-circuit situations
The VFD protects the motor and motor cable in a short-circuit situation when the motor cable is
dimensioned according to the rated current of the VFD. No additional protection devices are
needed.
If the VFD is connected to multiple motors, a separate thermal overload switch
or a circuit breaker must be used for protecting each cable and motor. These
devices may require a separate fuse to cut off the short-circuit current.
4.4.3 Protecting the motor against thermal overload
According to regulations, the motor must be protected against thermal overload and the current
must be switched off when overload is detected. The VFD includes a motor thermal protection
function that protects the motor and closes the output to switch off the current when necessary.
4.4.4 Implementing a bypass connection
It is necessary to set power frequency and variable frequency conversion circuits for the assurance
of continuous normal work of the VFD if faults occur in some significant situations.
In some special situations, for example, if it is only used in soft start, the VFD can be converted into
power frequency running after starting and some corresponding bypass should be added.
Never connect the supply power to the VFD output terminals U, V and W.
Power line voltage applied to the output can result in permanent damage to the
VFD.
If frequent shifting is required, employ mechanically connected switches or contactors to ensure that
the motor terminals are not connected to the AC power line and VFD output terminals
simultaneously.
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