ABB ACS850-04 series, Firmware Manual

Page: 79 / 296

Program features 79
User-definable load curve
The drive output can be limited by defining a user-definable load curve. In practice,
the user load curve consists of an overload and an underload curve, even though
neither is compulsory. Each curve is formed by five points that represent output
current or torque as a function of frequency.
An alarm or fault can be set up to occur when the curve is exceeded. The upper
boundary (overload curve) can also be used as a torque or current limiter.
Settings
Parameter group 34 User load curve (page 186 ).
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).
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 (page 199 ).