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•
For high inertia applications (i.e. where the load inertia is
more than 30 times larger than the motor inertia) a brake re-
sistor is recomended to avoid over-voltage trip during high
speed engagement of the fly-start function.
1-80 Function at Stop
Option:
Function:
Select the frequency converter function after a stop command or after the speed is ramped down
to the settings in par. 1-81
Min Speed for Function at Stop [RPM]
.
Available selections depend on par. 1-10
Motor Construction
:
[0] Asynchron:
[0] coast
[1] DC-hold
[2] Motor check, warning
[6] Motor check, alarm
[1] PM non salient:
[0] coast
[0] *
Coast
Leaves motor in free mode.
[1]
DC Hold/Motor Preheat
Energizes motor with a DC holding current (see par. 2-00
[2]
Motor check, warning
Issues a warning if the motor is not connected.
[6]
Motor check, alarm
Issues an alarm if the motor is not connected.
1-90 Motor Thermal Protection
Option:
Function:
The frequency converter determines the motor temperature for motor protection in two different
ways:
•
Via a thermistor sensor connected to one of the analog or digital inputs (par. 1-93
).
•
Via calculation (ETR = Electronic Thermal Relay) of the thermal load, based on the ac-
tual load and time. The calculated thermal load is comed with the rated motor current
I
M,N
and the rated motor frequency f
M,N
. The calculations estimate the need for a lower
load at lower speed due to less cooling from the fan incorporated in the motor.
[0]
No protection
If the motor is continuously overloaded and no warning or trip of frequency converter is wanted.
[1]
Thermistor warning
Activates a warning when the connected thermistor in the motor reacts in the event of motor
over-temperature.
[2]
Thermistor trip
Stops (trips) the frequency converter when the connected thermistor in the motor reacts in the
event of motor over-temperature.
[3]
ETR warning 1
[4] *
ETR trip 1
[5]
ETR warning 2
[6]
ETR trip 2
[7]
ETR warning 3
[8]
ETR trip 3
[9]
ETR warning 4
[10]
ETR trip 4
ETR (Electronic Thermal Relay) functions 1-4 will calculate the load
when set-up where they were selected is active. For example ETR-3
starts calculating when set-up 3 is selected. For the North American
market: The ETR functions provide class 20 motor overload protection
in accordance with NEC.
6 How to Programme
VLT HVAC Drive High Power Operating In-
structions
106
MG.11.F3.02 - VLT
®
is a registered Danfoss trademark
6