Rockwell Automation 7000L PowerFlex 7000 Medium Voltage AC Drive C Frame - Marine - Manual (Page 194)

4-18 Component Definition and Maintenance
7000L-UM302B-EN-P – June 2013 7000 ―C‖ Frame - Marine
Filter Capacitors
Filter capacitors are used on the motor side for all drives. The AFE
Rectifier option also includes filter capacitors on the line side. Refer
to Figure 4.1 (Cabling Cabinet for 18-pulse Rectifier), and Figure 4.2
(Cabling Cabinet for AFE Rectifier).
The filter capacitors are three-phase four-bushing units and ―oil-
filled‖. The three-phase capacitors are comprised of internal single-
phase units that are connected in a Y configuration. The neutral point
of the Y is connected to the fourth bushing, which is accessible and
can be used for neutral point voltage measurement or other
protection/diagnostics purposes. Depending on the drive
configuration, the fourth bushing may or may not be connected to
circuitry. The metal cases of the capacitors are grounded through a
stud on the capacitor housing.
The capacitors are equipped with internal ―bleeding resistors‖ to
discharge the capacitor and reduce its voltage below 50V in 5
minutes when left disconnected. A typical three-phase capacitor is
shown below:
Figure 4.14 – Motor Filter Capacitor
W A R N I N G W A R N I N G Allow 5-10 minutes for motor capacitors to
safely discharge voltage prior to opening
cabinet doors.
Filter Capacitor Cabinet