Rockwell Automation 20G PowerFlex 750-Series AC Drives - Manual (Page 41)

Rockwell Automation Publication 750-RM002B-EN-P - September 2013 41
Drive Configuration Chapter 1
Auxiliary Power Supply The optional Auxiliary Power Supply module, 20-750-APS, is designed to
provide power to a single drive’s control circuitry in the event incoming supply
power to the drive is removed or lost.
When connected to a user supplied 24V DC power source, the communication
network functions remain operational and on-line. A DeviceNet program can
also continue to run and control any associated input and outputs.
The auxiliary power supply module is designed to power all peripherals, I/O, and
connected feedback devices.
Bus Regulation Some applications create an intermittent regeneration condition. The following
example illustrates such a condition. The application is hide tanning, in which a
drum is partially filled with tanning liquid and hides. When the hides are being
lifted (on the left), motoring current exists. However, when the hides reach the
top and fall onto a paddle, the motor regenerates power back to the drive,
creating the potential for an overvoltage fault.
When an AC motor regenerates energy from the load, the drive DC bus voltage
increases unless there is another means, of dissipating the energy, such as a
dynamic braking chopper/resistor, or the drive takes some corrective action prior
to the overvoltage fault value.
Motoring Regenerating