Danfoss VLT Midi Drive FC 280, Operating Manual, Page: 36 / 82

Enter line-to-common direct axis inductance of
the PM motor.
If only line-to-line data is available, divide the
line-line value by 2 to achieve the line-common
(starpoint) value.
It is also possible to measure the value with an
inductance meter, which also takes the
inductance of the cable into account. Divide the
measured value by 2 and enter the result.
7. Parameter 1-40 Back EMF at 1000 RPM .
Enter line-to-line back EMF of the PM motor at
1000 RPM mechanical speed (RMS value). Back
EMF is the voltage generated by a PM motor
when no frequency converter is connected and
the shaft is turned externally. Back EMF is
normally specified for nominal motor speed or for
1000 RPM measured between 2 lines. If the value
is not available for a motor speed of 1000 RPM,
calculate the correct value as follows: For
example, if back EMF at 1800 RPM is 320 V, the
back EMF at 1000 RPM is:
Back EMF=(Voltage/
RPM)x1000=(320/1800)x1000=178.
Program this value for
parameter 1-40 Back EMF at
1000 RPM .
Test motor operation
1. Start the motor at low speed (100–200 RPM). If
the motor does not turn, check installation,
general programming, and motor data.
Parking
This function is the recommended option for applications
where the motor rotates at slow speed (for example
windmilling in fan applications).
Parameter 2-06 Parking
Current and parameter 2-07 Parking Time are adjustable.
Increase the factory setting of these parameters for
applications with high inertia.
Start the motor at nominal speed. If the application does
not run well, check the VVC
+ PM settings. Table 5.13 shows
recommendations in different applications.
Application Settings
Low inertia applications
I
Load
/I
Motor
<5
•
Increase the value for
parameter 1-17 Voltage filter time
const.
by factor 5–10.
•
Reduce the value for
parameter 1-14 Damping Gain .
•
Reduce the value (<100%) for
parameter 1-66 Min. Current at
Low Speed
.
Medium inertia
applications
50>I
Load
/I
Motor
>5
Keep calculated values.
High inertia applications
I
Load
/I
Motor
>50
Increase the values for
parameter 1-14 Damping Gain ,
parameter 1-15 Low Speed Filter Time
Const.
, and parameter 1-16 High
Speed Filter Time Const.
High load at low speed
<30% (rated speed) Increase the value for
parameter 1-17 Voltage filter time
const.
Increase the value for
parameter 1-66 Min. Current at Low
Speed
(>100% for longer time can
overheat the motor).
Table 5.13 Recommendations in Different Applications
If the motor starts oscillating at a certain speed, increase
parameter 1-14 Damping Gain . Increase the value in small
steps.
Starting torque can be adjusted in parameter 1-66 Min.
Current at Low Speed . 100% provides nominal torque as
starting torque.
5.4.3 Automatic Motor Adaptation (AMA)
To optimize compatibility between the frequency converter
and the motor in VVC
+
mode, run AMA.
•
The frequency converter builds a mathematical
model of the motor for regulating output motor
current, thus enhancing motor performance.
•
Some motors may be unable to run the complete
version of the test. In that case, select
[2] Enable
reduced AMA in parameter 1-29 Automatic Motor
Adaption (AMA) .
•
If warnings or alarms occur, see chapter 8.4 List of
Warnings and Alarms .
•
For best results, run this procedure on a cold
motor.
Commissioning
VLT
®
Midi Drive FC 280
34 Danfoss A/S © 10/2017 All rights reserved. MG07A402
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