Protecting The Motor And Motor Cable; Bypass Connection - Kruger Ecowatt Drive K120 Series Operation Manual

Ecowatt ® Drive K120 series
Input cable(single phase)
Note: Select the fuse according to operation manual. During short-circuit, the fuse will
protect input power cables to avoid damage to the VFD; when internal short-circuit
occurred to the VFD, it can protect neighboring equipment from being damaged.

3.3.2 Protecting the motor and motor cable

If the motor cable is selected according to the rated current of the VFD, the VFD can
perform short-circuit protection for the motor and motor cable. The VFD provides the
motor thermal overload protection function, which can protect the motor, and lock the
output and cut off the current when necessary.
 If the VFD is connected to multiple motors, an additional thermal

3.3.3 Bypass connection

In critical occasions, power-variable frequency conversion circuit is necessary to
ensure proper operation of the system when VFD fault occurs. In some special cases, for
example, only soft startup is needed, it will convert to power-frequency operation
directly after soft startup, corresponding bypass link is also needed.
 Do not connect the power supply to the VFD output terminals U, V
If frequent switchover is needed, you can use the switch/contactor which carries
mechanical interlock to ensure motor terminals are not connected to input power
cables and VFD output ends simultaneously.
Figure 3-12 Fuse configuration
overload switch or breaker must be used to protect the motor and
motor cable. Such a device may use the fuse to cut off the
short-circuit current.
and W. The voltage applied to the motor cable may cause
permanent damage to the VFD.
Fuse
-22-
Installation guidelines
VFD