18
Bus Regulation
Refer to the "Autotune Procedure for Sensorless Vector and Economizer" on
page 17
for a description of these tests.
After the Static or Dynamic Autotune, the Inertia test should be performed. The
motor shaft will rotate during the inertia test. During the inertia test the motor
should be coupled to the load to find an accurate value. The inertia test can be
performed during the Start-up routine on the LCD HIM. The inertia test can also be
run manually by setting [Inertia Autotune] to 1 “Inertia Tune”, and then starting the
drive.
Troubleshooting the Autotune Procedure
If any errors are encountered during the Autotune process, or the procedure is
aborted by the user:
•
drive parameters are not changed
•
the appropriate fault code will be displayed in the fault queue
•
[Autotune] parameter is reset to 0.
The following conditions will generate a fault during an Autotune procedure:
•
Incorrect stator resistance measurement
•
Incorrect motor flux current measurement
•
Load too large
•
Autotune aborted by user
•
Incorrect leakage inductance measurement
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 (dynamic braking chopper/resistor, etc.) of
dissipating the energy, or the drive takes some corrective action prior to the
overvoltage fault value.
With bus regulation disabled, the bus voltage can exceed the operating limit and the
drive will fault to protect itself from excess voltage.
70EC
700VC
700H
✔ ✔
Motoring
Regenerating