Parker AC890PX Series, Product Manual

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D-57
Programming
AC890PX AC Drive
V/F Shape
The function block allows the user to parameterise the Drive’s conventional V/F motor fluxing scheme. Three V/F shapes are
available, LINEAR LAW, FAN LAW and USER DEFINED:

Linear Law V/F shape should be used in applications requiring constant motor torque though out the speed range (e.g.
machine tools or hoists).

Fan Law V/F shape provides extra energy savings for fan or pump applications.

User Defined V/F shape provides a method for the user to define any profile. 10 user definable (x,y) points are provided.
Liner interpolation is used between each point. The drive also assumes the following points - (0%,0%) and (100%,100%) -
though these may be overridden. For example, (USER FREQ 1 = 0%, USER VOLTAGE 1 = 5%) takes precedence over
(0%, 0%).
For any of these V/F shapes the BASE FREQUENCY parameter (in the MOTOR INDUCTION function block) which is the
value of Drive output frequency at which maximum output volts is provided, can be set by the user.
Boost Parameters

Correct no-load motor fluxing at low Drive output frequencies can be achieved by setting the FIXED BOOST parameter.

Correct motor fluxing under load conditions is achieved by setting the AUTO BOOST parameter. The motor is correctly
fluxed when the FIELD FBK diagnostic in the FEEDBACKS function block reads 100.0% .

Additional FIXED BOOST can be applied during acceleration by setting the ACCELERTN BOOST parameter. This can be
useful for starting heavy/high stiction loads.
Saving Energy
An ENERGY SAVING mode is provided which, when enables under low load conditions in the steady state, attempts to
reduce the output voltage so that minimum energy is used.