Rockwell Automation 7000L PowerFlex Medium Voltage AC Drive (C Frame) - Classic Control - Manual (Page 360)

6-16 Component Definition and Maintenance
7000L-UM300I-EN-P – June 2013 7000 “C” Frame
Filter Capacitors
Filter capacitors are used on the motor side for all 18-pulse and
PWM rectifier drive options. The PWM rectifier option also includes
filter capacitors on the line side. Refer to Figure 2.11 (Capacitor
Cabinet) in Chapter 2.
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 an 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 a
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 6.14 – Motor Filter Capacitor
A T T E N T I O N A T T E N T I O N Allow 5-10 minutes for motor capacitors to
safely discharge voltage prior to opening cabinet
doors.
Filter Capacitor Cabinet