ABB ACS280, Firmware Manual, Page: 49 / 430

Program features 49
Settings and diagnostics
Parameter group 37 User load curve .
Events: A8BE ULC overload warning, A8BF ULC underload warning, 8001 ULC
underload fault, 8002 ULC overload faul

U/f ratio
The
U
/f function is only available in scalar motor control mode, which uses
frequency control.
The function has two modes: linear and squared.
In linear mode, the ratio of voltage to frequency is constant below the field
weakening point. This is used in constant torque applications where it may be
necessary to produce torque at or near the rated torque of the motor
throughout the frequency range
In squared mode, the ratio of the voltage to frequency increases as the square
of the frequency below the field weakening point. This is typically used in
centrifugal pump or fan applications. For these applications, the torque
required follows the square relationship with frequency. Therefore, if the
voltage is varied using the square relationship, the motor operates at improved
efficiency and lower noise levels in these applications.
The
U /f function cannot be used with energy optimization; if parameter 45.11
Energy optimizer
is set to
Enable
, parameter
97.20 U/f ratio
is ignored.
Settings and diagnostics
Parameter 97.20 U/f ratio (page 284 ).
Events: -