Danfoss VLT HVAC Drive FC 102, Руководство по программированию, Страница: 125 / 250

for 60 s. If still overloaded, the frequency converter
normally trips (causing the pump to stop by coasting) and
issues an alarm.
110
130BA260.10
105
100
95
60s
100
90.7
98
Current
% of rated
Time
Desired current>100%
Inverter
load
counter
Time
Warning Warning
~
~
Illustration 3.43 Output Current in Overload Condition
If the pump is unable to run continuously with the
demanded capacity, run it at reduced speed for a while.
Select parameter 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 ).
Parameter 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 with 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 issue an
alarm.
Status for the counter can be read in
parameter 16-35 Inverter Thermal .
If parameter 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 to for
example 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
Option: Function:
Is used in case of steady overload beyond the
thermal limits (110% for 60 s).
[0]
*
Trip Select [0] Trip to make the frequency converter trip
and issue an alarm.
[1] Derate [1] Derate to reduce 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).
14-90 Fault Level
Use this parameter to customise fault levels.
Option: Function:
[0] Off Use [0] Off with caution as it ignores all
warnings and alarms for the selected source.
[1] Warning
[2] Trip
Changing a fault level from default option
[3] Trip Lock to [2] Trip leads to the automatic
reset of the alarm. For alarms involving
overcurrent, the frequency converter has a
hardware protection that issues a 3-minute
recovery after 2 consecutive overcurrent
incidents, this hardware protection cannot
be overruled.
[3] Trip Lock
[4] Trip w. delayed
reset
Failure Alarm Off Warning Trip Trip Lock
Inverter overloaded 9 X X
Overcurrent 13 X D
Current limit 59 X
Table 3.18 Selection of Choice of Action when Selected Alarm Appears
Parameter Descriptions Programming Guide
MG11CE02 Danfoss A/S © 03/2015 All rights reserved. 123
3 3