Technical information

NOTE
This parameter is only available if 0-02 Motor Speed Unit is
set to [Hz].
3.3.11 1-9* Motor Temperature
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 (1-93 Thermistor Source).
•
Via calculation (ETR = Electronic
Thermal Relay) of the thermal
load, based on the actual 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.
1.21.0 1.4
30
10
20
100
60
40
50
1.81.6 2.0
2000
500
200
400
300
1000
600
t [s]
175ZA052.12
f
OUT
= 2 x f
M,N
f
OUT
= 0.2 x f
M,N
f
OUT
= 1 x f
M,N
(par. 1-23)
I
MN
(par. 1-24)
I
M
WARNING
In order to maintain PELV, all connections made to the
control terminals must be PELV, e.g. thermistor must be
reinforced/ double insulated
NOTE
Danfoss recommends using 24V DC as thermistor supply
voltage.
NOTE
The ETR timer function does not work when 1-10 Motor
Construction = [1] PM, non salient SPM.
NOTE
For correct operation of ETR function setting in 1-03 Torque
Characteristics must fit the application (see description of
1-03 Torque Characteristics).
1-91 Motor External Fan
Option: Function:
[0] * No No external fan is required, i.e. the motor is derated at
low speed.
[1] Yes Applies an external motor fan (external ventilation), so
no derating of the motor is required at low speed. The
upper curve in graph above (fout = 1 x fM,N) is
followed if the motor current is lower than nominal
motor current (see 1-24 Motor Current). If the motor
current exceeds nominal current, the operation time
still decreases as if no fan were installed.
Parameter Description
VLT
®
HVAC Drive Programming Guide
MG11CD02 - VLT
®
is a registered Danfoss trademark 47
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