Automatic Motor Adaptation, AMA
Automatic motor adaptation is a test algorithm that
measures the electrical motor parameters at a motor
standstill. This means that AMA itself does not supply
any torque.
AMA is useful when commissioning systems, where
the user wants to optimise the adjustment of the fre-
quency converter to the motor applied. This feature is
used in particular where the factory setting does not
adequately cover the motor in question.
There are two motor parameters that are of primary
significance in automatic motor adaptation: the stator
resistance, Rs, and the reactance at normal magnet-
ising level, Xs. Parameter 107 allows a choice of au-
tomatic motor adaptation, with determination of both
Rs and Xs, or reduced automatic motor adaptation
with determination of only Rs.
The duration of a total automatic motor adaptation var-
ies from a few minutes on small motors to more than
10 minutes on large motors.
Limitations and preconditions:
•
For AMA to be able to determine the motor
parameters optimally, the correct nameplate
data for the motor connected to the frequency
converter must be entered in parameters 102
to 106.
•
For the best adjustment of the frequency con-
verter, it is recommended to carry out AMA
on a cold motor. Repeated AMA runs may
lead to a heating of the motor that will result
in an increase of the stator resistance, Rs.
•
AMA can only be carried out if the rated motor
current is minimum 35% of the rated output
current of the frequency converter. AMA can
be carried out up to one oversize motor.
•
If a LC filter is inserted between the frequency
converter and the motor, it will only be pos-
sible to carry out a reduced test. If an overall
setting is required, remove the LC filter while
running a total AMA. After completion of the
AMA reinsert the LC filter.
•
If motors are coupled in parallel only use re-
duced AMA if any.
•
When using synchronous motors it is only
possible to make a reduced AMA.
•
Long motor cables can have an effect on the
implementation of the AMA function if their
resistance is bigger than the stator resistance
of the motor.
How to perform an AMA
1.
Press the [STOP/RESET] key
2.
Set motor nameplate data in parameters 102
to 106
3.
Select whether a total [ENABLE (RS,XS)]or
a reduced [ENABLE RS] AMA is required in
parameter 107
4.
Connect terminal 12 (24 VDC) to terminal 27
on the control card
5.
Press the [START] key or connect terminal
18 (start) to terminal 12 (24 VDC) to start the
automatic motor adaptation.
Now the automatic motor adaptation goes through four
tests (for reduced AMA only the first two tests). The
different tests can be followed in the display as dots
after the text
WORKING
in parameter 107:
1.
Initial error check where nameplate data and
physical errors are checked. Display shows
WORKING.
2.
DC test where the stator resistance is esti-
mated. Display shows
WORKING..
3.
Transient test where the leakage inductance
is estimated. Display shows
WORKING...
4.
.AC test where the stator reactance is esti-
mated. Display shows
WORKING....
NOTE
AMA can only be carried out if there are
no alarms during tuning.
Discontinue AMA
If the automatic motor adaptation is to be discontinued,
press the [STOP/RESET] key or disconnect terminal
18 from terminal 12.
The automatic motor adaptation ends up with one of
the following messages after the test:
VLT
®
5000 Series
196
MG.51.C5.22 - VLT
p
is a registered Danfoss trademark.
Summary of Contents for VLT 5000 Series
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