Danfoss VLT AQUA Drive Design Manual page 40

2. Introduction to VLT AQUA Drive
Using a digital input and 24 V as power supply:
Example: The frequency converter trips when the motor temperature is
too high.
Parameter set-up:
Thermal Protection
Set par. 1-90 Motor
2
Source
Set par. 1-93 Thermistor
Using a digital input and 10 V as power supply:
Example: The frequency converter trips when the motor temperature is
too high.
Parameter set-up:
Thermal Protection
Set par. 1-90 Motor
Source
Set par. 1-93 Thermistor
Using an analog input and 10 V as power supply:
Example: The frequency converter trips when the motor temperature is
too high.
Parameter set-up:
Set par. 1-90 Motor Thermal Protection
Set par. 1-93 Thermistor Source
Do not select a reference source.
Input
Digital/analog
Digital
Digital
Analog
NB!
Check that the chosen supply voltage follows the specification of the used thermistor element.
Summary
With the Torque limit feature the motor is protected for being overloaded independent of the speed. With the ETR the motor is protected for being over
heated and there is no need for any further motor protection. That means when the motor is heated up the ETR timer controls for how long time the
motor can be running at the high temperature before it is stopped in order to prevent over heating. If the motor is overloaded without reaching the
temperature where the ETR shuts of the motor, the torque limit is protecting the motor and application for being overloaded.
NB!
ETR is activated in par. and is controlled in par. 4-16 Torque
is set in par. 14-25 Trip Delay at Torque Limit
40
Thermistor Trip
to [2]
Digital Input 33
to [6]
Thermistor Trip
to [2]
Digital Input 33
to [6]
to Thermistor Trip [2]
to Analog Input 54 [2]
Supply Voltage
Volt
24 V
10 V
10 V
Limit Motor Mode
.
MG.20.N4.02 - VLT
Threshold
Cut-out Values
< 6.6 kΩ - > 10.8 kΩ
< 800Ω - > 2.7 kΩ
< 3.0 kΩ - > 3.0 kΩ
. The time before the torque limit warning trips the frequency converter
®
is a registered Danfoss trademark
®
VLT AQUA Drive Design Guide