Over-Voltage Region; Severe Over-Voltage Region; Under-Voltage Region - Kohler Curtis F Series Manual

Curtis AC F2-A, F4-A, F6-A Motor Controllers – FOS 4.5 – April 2022
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Beyond the default or a redefined normal operating window, the controller's actions for over- and
under-voltage conditions are both voltage and time-duration based. As illustrated in the graph
and following paragraphs, these responses are fixed. No parameters can change or modify the
hardware restrictions.
Regen Cutback, with a 64ms delay before the OV Fault
Drive current Cutback, with a 64ms delay before the UV Fault

Over-Voltage Region

There is no delay on the Over-Voltage cutback. There is a 64ms delay on asserting the OV fault. The
controller will seek to reduce the voltage by progressively reducing regen (motor-braking torque).
The Overvoltage Cutback fault (flash code 2-4) is set.

Severe Over-Voltage Region

Should the B+ voltage rise to this region, it triggers the Severe B+ Over-voltage fault (flash code 1-8).
Normal controller operation will cease.

Under-Voltage Region

There is no delay in the drive current reduction (motor torque) in this region. There is a 64ms delay
before the Under-voltage Cutback fault is asserted (flash code 2-3).
pg. 34 3 — APPLICATION-SPECIFIC FEATURES