User-Definable U/F Curve; Autophasing - ABB ACS850 Manual

User-definable U/f curve

The user can define a custom U/f curve (output voltage as a function of frequency).
The curve can be used in special applications where linear and quadratic U/f ratios
are not adequate (e.g. when motor break-away torque needs to be boosted).
Voltage (V)
Par. 38.13
Par. 38.12
Par. 38.11
Par. 38.10
Par. 38.09
Par.
Note: The U/f curve can be used in scalar control only, i.e, when
mode setting is Scalar.
Note: Each user-defined point must have a higher frequency and higher voltage than
the previous point.
WARNING! High voltage at low frequencies may result in poor performance
or motor damage due to overheating.
Settings
Parameter group 38 Flux ref

Autophasing

Autophasing is an automatic measurement routine to determine the angular position
of the magnetic flux of a permanent magnet synchronous motor or the magnetic axis
of a synchronous reluctance motor. The motor control requires the absolute position
of the rotor flux in order to control motor torque accurately.
Custom U/f ratio
38.04 Par. 38.05
(page 217).
Par. 38.06 Par. 38.07
Program features 67
f (Hz )
Par. 38.08
99.05 Motor ctrl