Electromagnetic Compatibility Guidelines for Machine Design
C-3
Installation Manual for Models ODM-005, ODM-005i, ODM-010, ODM-010i, ODM-020 and ODM-020i
mount the filter where the AC power enters the enclosure. “AC Line Filter Installation” shows a
good installation and a poor installation.
When multiple power cables enter an enclosure, an unfiltered line can contaminate a filtered line external
to the enclosure. Therefore, all lines must be filtered to be effective. The situation is similar to a leaky
boat. All the holes must be plugged to prevent sinking.
If the filter is mounted excessively far from the drive, it may be necessary to mount it to a grounded
conductive surface, such as the enclosure, to establish a high frequency (HF) connection to that surface.
To achieve the HF ground, direct contact betweeb the mounting surface and the filter must be achieved.
This may require removal of paint or other insulating material from the cabinet or panel.
The only reasonable filtering at the drive output terminals is the use of inductance. Capacitors would slow
the output switching and deteriorate the drive performance. A common mode choke, as is used in the
OMNIDRIVE, can be used to reduce the HF voltage at the drive output. This will reduce emission coupling
through the drive back to the AC line. However, the motor cable still carries a large HF voltage and
current. Therefore, it is very important to segregate the motor cable from the AC power cable. More
information on cable shielding and segregation is contained in the section on shielding.
Intro
F
IGURE
11.2
AC Line Filter Installation
Intro
!
WARNING
Large leakage currents exist in AC line filters. They must be grounded properly
before applying power. Filter capacitors retain high voltages after power
removal. Before handling the equipment, voltaged should be measured to deter-
mine safe levels prior to handling the equipment. Failure to observe this
precation could result in severe bodily injury.
AC
LINE
RADIATED
EMI
DRIVE
RADIATED
EMI
FILTER
CONDUCTED EMI
CONDUCTED EMI
POOR
AC
LINE
DRIVE
RADIATED
EMI
FILTER
CONDUCTED EMI
GOOD
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