Omron SX inverter manual

• The screening must be connected with a large
contact surface of preferable 360 and always at
both ends, to the motor housing and the VSD
housing. When painted mounting plates are used,
do not be afraid to scrape away the paint to obtain
as large contact surface as possible at all mounting
points for items such as saddles and the bare
cable screening. Relying just on the connection
made by the screw thread is not sufficient.
NOTE: It is important that the motor housing has the
same earth potential as the other parts of the machine.
• The litz ground connection, see fig. 16, is only necessary
if the mounting plate is painted. All the variable
speed drives have an unpainted back side and
are therefore suitable for mounting on an unpainted
mounting plate.
Connect the motor cables according to U - U, V - V
and W - W.
Pay special attention to the following points:
• If paint must be removed, steps must be taken to
prevent subsequent corrosion. Repaint after making
connections!
• The fastening of the whole variable speed drive
housing must be electrically connected with the
mounting plate over an area which is as large as
possible. For this purpose the removal of paint is
necessary. An alternative method is to connect the
variable speed drive housing to the mounting plate
with as short a length of litz wire as possible.
• Try to avoid interruptions in the screening wherever
possible.
• If the variable speed drive is mounted in a standard
cabinet, the internal wiring must comply with the
EMC standard. Fig. 15 shows an example of a
VSD built into a cabinet.
VSD built into cabinet
NOTE: The terminals DC-, DC+ and R are options.
Switches between the motor and the
VSD
If the motor cables are to be interrupted by maintenance
switches, output coils, etc., it is necessary that
the screening is continued by using metal housing,
metal mounting plates, etc. as shown in the Fig. 15.
Fig. 16 shows an example when there is no metal
mounting plate used (e.g. if IP54 variable speed drives
are used). It is important to keep the “circuit” closed,
by using metal housing and cable glands.
Litz
RFI-Filter
(option)
Mains
VSD
Motor
Metal EMC cable glands
Output coil (option)
Screened cables
Unpainted mounting plate
Metal connector housing
Screen connection
of signal cables
Mains
(L1,L2,L3,PE)
Metal coupling nut
Motor
Brake resistor
(option)
Fig. 15 Variable speed drive in a cabinet on a mounting plate
Fig. 16 shows an example when there is no metal
mounting plate used (e.g. if IP54 variable speed drives
are used). It is important to keep the “circuit” closed,
by using metal housing and cable glands.
PE
Motor cable
shield connection
Fig. 14 Screen connection of cables.
18 Installation Omron SX inverter manual