Variable speed drives/frequency converters
Variable speed drives/
Each Husqvarna PG 680 & 820 is equipped with 2
variable speed drive or frequency converter. This
unit is incorporated into the machine for the following
Manipulate incoming power to enable increase/
decrease in speed & direction change.
Regulate current and voltage supply to the motors
to ensure motors run at optimum levels (e.g.
Monitors incoming power to ensure suitability for
machine and application being performed.
Controls current being drawn by motors to ensure
motors are running within safe operational limits (to
prevent damage to motor).
Monitors load on machine to ensure the grinder is
not being overloaded thus offering protection for
belt, bearings and other internal components.
Protects motors from faulty power supply (e.g. run-
ning on 2 phases).
Identiﬁ es electrical faults with the machine and
registers fault code.
Has monitoring menus that help isolate cause of
potential electrical faults.
Monitoring menus also enable operator to gauge
how hard machine is working. Whilst it is not essen-
tial for an operator to intimately know every feature
of the variable speed drives or frequency convert-
ers, it is useful to be familiar with both the fault
codes as well as some of the monitoring menus.
Each variable speed drive or frequency converter has
a keypad which will appear as illustrated on the right
when the machine has power connected to it.
1. Run direction (fwd or rev)
2. Indicates if unit is either stopped or running
3. Up key
4. Left key
5. Down key
6. Reset button
7. Output mode (Hertz in this example)
8. Output value