2 device protection, 3 motor protection, Device protection – Lenze EVF9383 User Manual
Page 61: Motor protection

Important notes
Device protection
5.1
5.1.2
l
5.1−3
EDSVF9383V EN 7.1−04/2012
5.1.2
Device protection
ƒ In the event of condensation, connect the controller to the mains
voltage only after the humidity has evaporated.
ƒ The controller is protected by external fuses.
ƒ Length of the screws for connecting the shield sheet for the control
cables: 12 mm.
ƒ Cyclic connection and disconnection of the supply voltage can overload
and destroy the input current limitation of the controller. In case of
cyclic mains switching over a longer period of time, the controller must
not be switched on more frequently than every 5 minutes!
ƒ Switching on the motor side of the controller is only permitted for
emergency switch−off.
ƒ Provide unused control inputs and outputs with terminal strips. Cover
unused Sub−D sockets with protective covers included in the scope of
supply.
5.1.3
Motor protection
ƒ Extensive protection against overload:
– By overcurrent relays or temperature monitoring.
– We recommend the use of PTC thermistors or thermostats to monitor
the motor temperature.
– PTC thermistors or thermostats can be connected to the controller.
– For monitoring the motor, we recommend the use of the I
2
xt
monitoring.
ƒ Only use motors with an insulation suitable for the inverter operation:
– Insulation resistance: min. û = 1.5 kV, min. du/dt = 5 kV/
ms
– When using motors with an unknown insulation resistance, please
contact your motor supplier.
)
Note!
To avoid bearing currents, Lenze recommends to use motors
with insulated non−drive end bearings. Optionally, motor chokes
can be used to reduce bearing currents.