Lenze EDB9300UES - Manual (Page 80)

Transport, Installation and Connection
BA8230 75
Notes on motor winding insulation
With mains supply voltages U
N
of up to 460 V it is possible to use standard motors or
motors with equivalent insulation characteristics with the 8230 frequency inverter. The
400 ... 460 V standard motors are designed for the voltage rates of rise and voltage
peaks of up to 1300 V which occur during inverter operation. When using motors from
other manufacturers it may be necessary to contact the supplier concerning the
suitability of motors for inverter operation. 8230 frequency inverter motor filters are to
be used if the insulation resistance of the motors and the max. permitted voltage in
the motor terminal box do not match the 1300 V required and the permitted voltage
rate of rise for the winding insulation is < 3 kV/µs. If the motors do not meet these
requirements, 8230 frequency inverter motor filters or motor chokes are to be
provided.
Installation notes, braking resistors
All braking resistors are to be connected via short cables. Cable bundles are to be laid
separately from other cables. For EMC reasons we recommend using only screened
cables. The screen must be earthed at both ends and connected to the casing.
The cable cross-sections must be rated at least according to the overcurrent
protection device.
Braking resistors carry dangerous voltages to earth and must be protected so that
they cannot be touched.
Braking resistors are to be installed externally so that the cooling air and the ambient
temperature for 8230 frequency inverter units are not affected by the heat generated
by the braking resistors.
An unrestricted flow of cooling air is essential for the braking resistors. The waste heat
is emitted upwards. A minimum clearance of 200 mm is to be provided from adjacent
components, walls, roofs or similar.
As electrical energy is converted in braking resistors the air and certain parts of the
casing will inevitably become hot. The temperature may rise to 150 °K above the
ambient temperature.
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