Danfoss VLT HVAC Drive Instruction Manual page 78

6. How to program the adjustable frequency
drive
1-80
Value:
Coast
DC hold/Preheat
Function:
Select the adjustable frequency drive function
after a stop command or after the speed is
1-90 Motor Thermal Protection
Option:
6
[0]
[1]
[2]
78
Function at Stop
Function:
The frequency converter determines the motor temperature for
motor protection in two different ways:
•
•
No protection If the motor is continuously overloaded and no warning or trip
of frequency converter is wanted.
Thermistor warning Activates a warning when the connected thermistor in the motor
reacts in the event of motor over-temperature.
Thermistor trip Stops (trips) the frequency converter when the connected ther-
mistor in the motor reacts in the event of motor over-tempera-
ture.
The thermistor cut-out value is > 3 kΩ.
MG.11.A4.22 - VLT
VLT
ramped down to the settings in par. 1-81
Speed for Function at Stop [RPM]
Coast
Select [0] to leave the motor in free
mode.
DC hold/Preheat
Select
[0]
motor with a DC holding current (see par.
[1]
2-00).
Via a thermistor sensor connected to one of the analog
Thermistor Source
or digital inputs (par. 1-93
Via calculation (ETR = Electronic Thermal Relay) of the
thermal load, based on the actual load and time. The
calculated thermal load is compared with the rated
motor current I and the rated motor frequency
M,N
f . The calculations estimate the need for a lower
M,N
load at lower speed due to less cooling from the fan
incorporated in the motor.
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® HVAC Drive Instruction Manual
Min
.
[1] to energize the
).