Salicru CV30, User Manual, Page: 21 / 140

Installation Guidelines 21 - 140
3.3 Layout protection
3.3.1 Protecting the inverter and input power cable in short-circuit situations
Protect the inverter and input power cable in short circuit situations and against thermal overload.
Arrange the protection according to the following guidelines.
Figure 3-14 Fuse configuration
Note: Select the circuit breaker as the manual indicated. The circuit breaker will protect the input power
cable from damage in short-circuit situations. It will protect the surrounding devices when the internal of the
inverter is short circuited.
3.3.2 Protecting the motor and motor cables
The inverter protects the motor and motor cable in a short-circuit situation when the motor cable is
dimensioned according to the rated current of the inverter. No additional protection devices are needed.
 If the inverter 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 also may require a separated circuit breaker to cut off the short-circuit
current.
3.3.3 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 inverter if faults occur in some significant situations.
In some special situations, for example, if it is only used as soft start, the inverter can be conversed into
power frequency running after starting and some corresponding bypass should be added.
 Never connect the supply power to the inverter output terminals U, V and W.
Power line voltage applied to the output can result in permanent damage to the
inverter.
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 inverter output terminals simultaneously.