Output Connections - WEG CFW-11 User Manual

3.2.3.3 Output Connections

ATTENTION!
The inverter has an electronic motor overload protection that shall be adjusted according to the
driven motor. When several motors are connected to the same inverter, install individual overload
relays for each motor.
ATTENTION!
The motor overload protection available at the CFW-11 is in accordance with the IEC60947-4-2
and UL508C standards.
Important considerations for the UL508C:
Trip current equal to 1.25 times the motor rated current (P0401) adjusted in the oriented start-up
menu.
The parameter P0159 maximum setting (Motor Thermal Class) is 3 (Class 20).
The parameter P0398 maximum setting (Motor Service Factor) is 1.15.
ATTENTION!
If a disconnect switch or a contactor is installed between the inverter and the motor, never operate
them with a spinning motor or with voltage at the inverter output.
The characteristics of the cable used for the inverter and motor interconnection, as well as the physical location
are extremely important to avoid electromagnetic interference in other equipment and to not affect the life cycle
of motor windings and motor bearings controlled by inverters.
Recommendations for the motor cables:
Unshielded Cables:
Can be used when it is not necessary to meet the European directive of electromagnetic compatibility
(89/336/EEC).
Keep motor cables away from other cables (signal cables, sensor cables, control cables, etc.), according to
table 3.5.
The emission of the cables may be reduced by installing them inside a metal conduit, which shall be grounded
at both ends.
Connect a fourth cable between the motor ground and the inverter ground.
Note:
The magnetic field created by the current circulation in these cables may induce current in close metal pieces, heat
them, and cause additional electrical losses. Therefore, keep the 3 (three) cables (U, V, W) always together.
Shielded Cables:
Are mandatory when the electromagnetic compatibility directive (89/336/EEC) shall be met, as defined by
the standard EN 61800-3 "Adjustable Speed Electrical Power Drive Systems". These cables act mainly by
reducing the irradiated emission in the radio-frequency range.
In reference to the type and details of installation, follow the recommendations of IEC 60034-25 "Guide
for Design and Performance of Cage Induction Motors Specifically Designed for Converter Supply" – refer
to a summary in figure 3.15. Refer to the standard for further details and eventual modifications related to
new revisions.
Installation and Connection
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