GEH-7252
44
May 2003
GE Capacitor & Power Quality Products
g
6. FILTER DESCRIPTION
The GE Matrix Filter is a low pass filter
containing proprietary technology, which makes
it particularly useful for harmonic mitigation of
adjustable speed drives. Figure 38 shows a
block diagram of the filter. Three phase AC
power is connected to the input section which
contains a three phase AC reactor and circuitry
which inhibits oscillation of the filter with the AC
power system. The center leg consists of a
series reactor and capacitor bank. Because of
the capacitor bank the filter operates with
leading power factor at all loads, but unlike trap
filters the GE Matrix Filter does not produce
significant voltage rise at the point of common
coupling with the power system. The standard
8% filter output section consists of an AC
output reactor.
The 5% filter is comprised of a standard 8%
filter plus an additional input reactor.
Matrix filters are suitable for use with AC and
DC drives and they can be used in both
regenerative and non-regenerative applications
when properly selected.
Filters for variable torque AC drives rated 7.5
Hp and above should be selected for a filter
output current rating greater than or equal to
the motor current rating. If the motor current
rating is not available, use the NEC motor
current rating.
Filters for variable torque AC drives rated 2 – 5
Hp should be selected for a filter output current
rating greater than or equal to 105% of the
motor current rating. If the motor current rating
is not available, select on the basis of 105% of
the NEC motor current rating.
Filters for variable torque AC drives rated less
than 1.5 Hp should be selected for an output
current rating greater than or equal to 110% of
the motor current rating or 110% OF the NEC
motor current rating.
For constant torque, AC and DC drive
applications operating from six pulse rectifier
front ends selected a filter current rating
according to application engineering note
“Matrix Filter Operation in Constant Torque
Applications with Six Pulse Rectifiers” or
consult GE engineering. For phase controlled
DC drive applications, select filter current rating
per application note “Matrix Filter with Phase
Controlled DC Drivers.
Where a single filter is used to feed multiple
drives, the output current rating of the filter
should be selected to equal the total current
rating of the individual drives when calculated
according to the instructions above.
Because the filter supplies harmonic currents
required by the drive, linear loads (such as
space heaters, incandescent lighting and AC
motors operated across the line) should not be
connected to the output of the filter
.
