Danfoss VLT AQUA Drive FC 200 Programming Manual page 116

Parameter Description
NOTICE!
This parameter cannot be adjusted while motor is running.
3 3
14-59 Actual Number of Inverter Units
Range:
Size related
*
3.13.6 14-6* Auto Derate
This group contains parameters for derating the adjustable
frequency drive in case of high temperature.
14-60 Function at Overtemperature
If either heatsink or control card temperature exceeds a
programmed temperature limit, a warning will be activated. If
the temperature increases further, select whether the adjustable
frequency drive should trip (trip locked) or derate the output
current.
Option:
[0] Trip
[1] Derate
3.13.7 No Trip at Inverter Overload
In some pump systems, the adjustable frequency drive has
not been sized properly to yield the current needed in all
points of the operational flow-head characteristic. At these
points, the pump will need a current higher than the rated
current of the adjustable frequency drive. The adjustable
frequency drive can yield 110% of the rated current contin-
uously for 60 s. If still overloaded, the adjustable frequency
drive will normally trip (causing the pump to stop by
coasting) and provide an alarm.
3-90
Function:
[ 1 - 1 ] Sets the actual number of operating
inverter units.
Function:
The adjustable frequency drive will trip
(trip locked) and generate an alarm.
Power must be cycled to reset the alarm,
but will not allow restart of the motor
until the heatsink temperature has
dropped below the alarm limit.
If the critical temperature is exceeded,
the output current will be reduced until
the allowable temperature has been
reached.
MG20O622 - VLT
®
VLT AQUA Drive Programming Guide
Current
% of rated
Inverter
load
counter
Figure 3.42
It may be preferable to run the pump at reduced speed for
a while in cases where it is not possible to run contin-
uously with demanded capacity.
Select 14-61 Function at Inverter Overload to automatically
reduce pump speed until the output current is below
100% of the rated current (set in 14-62 Inv. Overload Derate
Current).
14-61 Function at Inverter Overload is an alternative to
letting the adjustable frequency drive trip.
The adjustable frequency drive estimates the load on the
power section by means of an inverter load counter, which
will cause a warning at 98% and a reset of the warning at
90%. At the value 100%, the adjustable frequency drive
trips and provides an alarm.
Status for the counter can be read in 16-35 Inverter
Thermal.
If 14-61 Function at Inverter Overload is set to [3] Derate, the
pump speed will be reduced when the counter exceeds
98, and stay reduced until the counter has dropped below
90.7.
If 14-62 Inv. Overload Derate Current is set, for example, to
95% a steady overload will cause the pump speed to
fluctuate between values corresponding to 110% and 95%
of rated output current for the adjustable frequency drive.
®
is a registered Danfoss trademark
110
105
100
95
~ ~
60s
Desired current>100%
100
98
90.7
Warning Warning
Time
Time