Auto Derate; No Trip At Inverter Overload; Inductance Output Filter; Function At Over Temperature - Danfoss VLT AutomationDrive FC 302 Programming Manual

Parameter Descriptions
14-56 Capacitance Output Filter
Compensation function of the LC filter requires the per phase
equivalent star-connected capacitance of the filter (3 times the
capacity between 2 phases when capacitance is delta
connection).
Range: Function:
NOTICE
This is required for correct
compensation in flux mode
(parameter 1-01 Motor Control
Principle).

14-57 Inductance Output Filter

Range: Function:
Size [0.001 - Set the inductance of the output filter.
related 65 mH] The value can be found on the filter
*
label.
NOTICE
This is required for correct
compensation in flux control
principle (parameter 1-01 Motor
Control Principle).
14-59 Actual Number of Inverter Units
Range: Function:
Size related [ 1 - 1 ] Set the actual number of power units.
*

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.
MG33MP02
Programming Guide

3.14.7 No Trip at Inverter Overload

In some 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 motor 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 motor to stop by coasting) and issues an
alarm.
Current
% of rated
Inverter
load
counter
Illustration 3.64 Output Current in Overload Condition
If the motor 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 motor 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 motor 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.
Danfoss A/S © 10/2018 All rights reserved.
110
105
100
95
~ ~
60s
Desired current>100%
100
98
90.7
Warning Warning
3 3
Time
Time
199