Rockwell Automation 20Y PowerFlex Active Front End - Manual (Page 72)

72 Rockwell Automation Publication 20Y-UM001E-EN-P - July 2014
Chapter 2 AFE in IP21 Rittal Enclosure—Installation/Wiring
Using the AFE with
PowerFlex Drives When the Active Front End is used with drives that have common mode
capacitors (for example, PowerFlex 7-Class or PowerFlex 750-Series drives), the
common mode capacitors of these drives must be disconnected. See the
documentation of the respective drives.
When supplying power to PowerFlex drives of different frame sizes on the same
DC bus, additional bus capacitance may be needed. For details, see Drives in
Common Bus Configurations, publication DRIVES-AT002.
Control Wiring The AFE in a IP21 Rittal enclosure is factory wired and programmed to operate
from the operator switches on the front of the enclosure. See
Table 17 and
Figure 36 for I/O terminal designations. Only when a customized (or remote)
control is required, will the control wiring and correspondent digital I/O
parameter setting need to be changed.
Here are some important points to remember about I/O wiring:
• Always use copper wire.
• Wire with an insulation rating of 600V or greater is recommended.
• Control and signal wires must be separated from power wires by at least 0.3
meters (1 foot).
• When it is unavoidable to cross control and signal wires with power wires,
always cross power wires at a 90° angle.
IMPORTANT I/O terminals labeled ‘(–)’ or ‘Common’ are not referenced to earth ground.
They are designed to greatly reduce common mode interference. Grounding
these terminals can cause signal noise.
ATTENTION: Inputs must be configured with software and jumpers (see Analog
I/O Configuration on page 76 ). Also, configuring an analog input for 0-20 mA
operation and driving it from a voltage source can cause component damage.
Verify proper configuration before applying input signals.
ATTENTION: It is important to disable the variable frequency drives that are
connected to the AFE output when the AFE is not active (not modulating). This
can be done by either connecting the 'Inverter Enable' output of the AFE to each
variable frequency drive’s enable input, or by enabling parameter 132 [Contact
Off Cnfg] to force the main contactor off in case of a fault. This ensures that once
the AFE stops modulating, there is no motoring current flowing through the AFE
IGBT diodes. Failure to disable the AFE output can result in component damage
or a reduction in product life.
When enabling parameter 132, see page 105 for details. The AFE is shipped with
parameter 132 disabled. This will not stop or shut down DC output when a fault
occurs.