Danfoss VLT FC 100 Series Programming Manual page 53

Parameter Description
3.3.11 1-9* Motor Temperature
1-90 Motor Thermal Protection
3 3
Option:
[0] No protection
[1] Thermistor
warning
[2] Thermistor trip Stops (trips) the Adjustable frequency drive
[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 the 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.
3-26
®
VLT HVAC Drive Programming Guide
Function:
The Adjustable frequency drive 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 compared with the rated
motor current I and the rated
M,N
motor frequency f . The
M,N
calculations estimate the need for
a lower load at lower speed due
to less cooling from the fan
incorporated in the motor.
If the motor is continuously overloaded
and no warning or trip of adjustable
frequency drive is wanted.
Activates a warning when the connected
thermistor in the motor reacts in the event
of motor overtemperature.
when the connected thermistor in the
motor reacts in the event of motor
overtemperature.
MG11CD22 - VLT
t [s]
2000
1000
600
500
400
300
200
100
60
50
40
30
20
10
1.0 1.2 1.4
Figure 3.10
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
that 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.
® is a registered Danfoss trademark
fOUT = 1 x f M,N
fOUT = 2 x f M,N
fOUT = 0.2 x f M,N
IM
1.6 1.8 2.0 IMN