Lenze 8400 - Manual (Page 159)

Electrical installation
Important notes
Maximum motor cable length
6

159 EDS84ASC552 EN 9.1
6.1.3 Maximum motor cable length
ƒ Ensure that the motor cable is as short as possible to have a positive effect on the
drive behaviour.
ƒ
In group drives (multiple motors on one controller), the resulting cable length l
res
is
the crucial factor:
I
res
[m] = (l
1
+ l
2
+ l
3
... + l
i
) ⋅ i  l
x
Length of the individual motor cable
l
res
Resulting length of the motor cable
i Number of individual motor cables
ƒ The ”technical data” (chap. 4.1) provided for the motor cable length must be
observed.
6.1.4 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/s
– When using motors with an unknown insulation resistance, please contact your
motor supplier.
6.1.5 Interaction with compensation equipment
ƒ Controllers only consume very little reactive power of the fundamental wave from
the AC supply mains. Therefore, a compensation is not required.
ƒ If the controllers are connected to a supply system with compensation equipment,
this equipment must comprise chokes.
– For this, contact the supplier of the compensation equipment.