3.14.6 14-6* Auto Derate
This group contains parameters for derating the frequency
converter if there is high temperature.
14-60 Function at Over Temperature
Option: Function:
If either heat sink or control card
temperature exceeds a factory-
programmed temperature limit, a
warning is activated. If the
temperature increases further, select
whether the frequency converter
should trip (trip lock) or derate the
output current.
[0] * Trip The frequency converter trips (trip
lock) and generates an alarm. Cycle
power to reset the alarm. The
motor restarts when 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.
3.14.7 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 ow-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
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 3.50 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 issues 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
uctuate between values corresponding to 110% and 95%
of rated output current for the frequency converter.
Parameter Descriptions
VLT
®
HVAC Drive FC 102
154 Danfoss A/S © 10/2019 All rights reserved. M0010001
33
To Next Page
Loading...
Need help?
General