Set
1-93 Thermistor Source
to
[6] Digital Input 33
PTC / Thermistor
R
OFF
ON
<800 Ω
+10V
130BA152.10
>2.7 kΩ
12 13
18
37
32
27
19
29
33 20
55
50
39 42
53 54
Illustration 2.43 Using a Digital Input and 10 V as Power
Supply
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
1-90 Motor Thermal Protection
to
[2] Thermistor Trip
Set
1-93 Thermistor Source
to
[2] Analog Input 54
Do not select a reference source.
55
50
39 42
53 54
R
<3.0 k
Ω
>3.0 k
Ω
+10V
130BA153.11
PTC / Thermistor
OFF
ON
Illustration 2.44 Using an Analog Input and 10 V as Power
Supply
Input
Digital/analog
Supply Voltage
V
Cut-out Values
Threshold
Cut-out Values
Digital
24
< 6.6 k
Ω
- > 10.8 k
Ω
Digital
10
< 800
Ω
- > 2.7 k
Ω
Analog
10
< 3.0 k
Ω
- > 3.0 k
Ω
Table 2.26 Threshold Cut-out Values
NOTICE
Check that the chosen supply voltage follows the specifi-
cation 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 to prevent overheating. 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.
ETR is activated in
1-90 Motor Thermal Protection
and is
controlled in
4-16 Torque Limit Motor Mode
. The time
before the torque limit warning trips the frequency
converter is set in
14-25 Trip Delay at Torque Limit
.
Introduction to VLT® HVAC D...
Design Guide
MG11BC02
Danfoss A/S © Rev. 06/2014 All rights reserved.
51
2
2
