Danfoss VLT AQUA Drive FC 202 Programming Manual page 119

Parameter Description
3.13.7 14-6* Auto Derate
This group contains parameters for derating the frequency
converter in case of high temperature.
14-60 Function at Over Temperature
If either heat sink or control card temperature exceeds a
programmed temperature limit, a warning is activated. If the
temperature increases further, select whether the frequency
converter should trip (trip locked) or derate the output current.
Option: Function:
[0] Trip The frequency converter trips (trip locked)
and generates an alarm. Power must be
cycled to reset the alarm, but does not
allow restart of the motor until the heat sink
temperature has dropped below the alarm
limit.
[1] Derate If the critical temperature is exceeded the
output current is reduced until the
allowable temperature has been reached.
3.13.8 No Trip at Inverter Overload
In some pump systems, the frequency converter has not
been sized properly to yield the current needed in all
points of the operational flow-head characteristic. At these
points, the pump needs a current higher than the rated
current of the frequency converter. The frequency
converter can yield 110% of the rated current continuously
for 60 s. If still overloaded, the frequency converter
normally trips (causing the pump to stop by coasting) and
provides an alarm.
Current
% of rated
110
105
100
95
~ ~
60s
Desired current>100%
Inverter
load
counter
100
98
90.7
Warning
Illustration 3.44 Output Current in Overload Condition
It may be preferable to run the pump at reduced speed for
a while in case it is not possible to run continuously with
demanded capacity.
MG20O702
Programming Guide
Time
Time
Warning
Danfoss A/S © Rev. 2014-01-21 All rights reserved.
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 parameter 14-62 Inv.
Overload Derate Current).
14-61 Function at Inverter Overload is an alternative to
letting the frequency converter trip.
The frequency converter estimates the load on the power
section by means of an inverter load counter, which causes
a warning at 98% and a reset of the warning at 90%. At
the value 100%, the frequency converter trips and provides
an alarm.
Status for the counter can be read in
parameter 16-35 Inverter Thermal.
If 14-61 Function at Inverter Overload is set to [3] Derate, the
pump speed is reduced when the counter exceeds 98, and
stays reduced until the counter has dropped below 90.7.
If parameter 14-62 Inv. Overload Derate Current is set e.g. to
95%, a steady overload causes the pump speed to
fluctuate between values corresponding to 110% and 95%
of rated output current for the frequency converter.
14-61 Function at Inverter Overload
Is used in case of steady overload beyond the thermal limits
(110% for 60 s).
Option: Function:
[0] Trip The frequency converter trips and provides an alarm.
[1] Derate Reduces pump speed to decrease the load on the
power section and allowing this to cool down.
14-62 Inv. Overload Derate Current
Range: Function:
95 % [50 - 100 Defines the desired current level (in % of
*
%] rated output current for the frequency
converter) when running with reduced pump
speed after load on the frequency converter
has exceeded the allowable limit (110% for
60 s).
3.13.9 14-9* Fault Settings
14-90 Fault Level
Option: Function:
[0] Off Use this parameter to customise fault
levels. Use [0] Off with caution as it
ignores all warnings and alarms for the
selected source.
[1] Warning
[2] Trip
[3] Trip Lock
[4] Trip w. delayed
reset
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