4
Requirements for EMC compliance
• Keep parallel runs of power and control cables at least
0.3 metres apart. Cross-overs must be at right angles.
• Keep sensitive components at least 0.3 metres from
the drive and power supply cables.
•
The AC connections from the filter to the drive must be
less than 0.3 metres or, if longer, correctly screened.
•
Do not run filtered and unfiltered AC supply cables
together.
•
Control signals must be filtered or suppressed, e.g.
control relay coils and current carrying contacts. The
drive module has built-in filters on signal outputs.
•
The AC supply filter must have a good earth connection
to the enclosure back plane. Take care with painted
metal to ensure good conductivity.
•
The AC input filter has earth leakage currents. Earth
RCD devices may need to be set at 5% of rated current.
•
The metal enclosure will be RF ground. The AC filter,
drive earth and motor cable screen should connect
directly to the metal cabinet for best performance.
• Linear control signal cables must be screened, with
the screen earthed at the drive end only. Minimise the
length of screen stripped back and connect it to an
analogue earth point.
•
(1)
The motor cable must be screened or armoured
with 360 degree screen terminations to earth at each
end. The cable must have an internal earth cable and
the screen must extend into the enclosure and motor
terminal box to form a Faraday cage without gaps.
•
(2)
The internal earth cable must be earthed at each
end. The incoming earth must be effective at RF.
WARNING! The earth safety must always take
precedence.
5
5 Requirements for EMC compliance
Requirements for EMC compliance
WARNING!
ELECTRIC SHOCK HAZARD
AC supply filters
must not be used
on supplies that
are unbalanced or
float with respect to
earth.
The drive and AC
filter must only
be used with a
permanent earth
connection. No
plugs/sockets are
allowed in the AC
supply.
The AC supply
filter contains high
voltage capacitors
and should not
be touched for a
period of at least 20
seconds after the
removal of the AC
supply.
DRIVE
CONTROL
TERMINALS
DRIVE
AC SUPPLY
INPUTS
DRIVE
EARTH
TERMINAL
ARMATURE
AND FIELD
OUTPUTS
CONTROL
SIGNAL
FILTERS
AC SUPPLY
FILTER
UNIT
*
dc drive module
User’s metal enclosure
1
2
Figure 3 Connections for EMC compliance
