Danfoss VT2800 Series Design Manual page 70

NB!:
The max. value equals f
set in parameter 104 Motor frequency, f
107 Automatic motor tuning, AMT
(AUTO MOTOR TUN.)
Value:
Optimisation off (AMT OFF)
Optimisation on (AMT START)
Function:
NB!:
AMT is not possible on VLT 2880-82.
Automatic motor tuning is an algorithm that measures
stator resistance R without the motor axle turning.
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This means that the motor is not deli v ering any torque.
AMT can be used with benefit when initialising units
where the user wishes to optimise adjustment of
the frequency converter to the motor being used.
This is used in particular when the factory setting
does not sufficiently cover the motor.
For the best possible tuning of the frequency converter
it is recommended that AMT is performed on a
cold motor. It should be noted that repeated AMT
runs can cause heating of the motor, resulting
in an increase in the stator resistance R
rule, however, this is not critical.
AMT is performed as follows:
Start AMT:
1. Gi v e a STOP signal.
2. Parameter 107 Automatic motor tuning is set
at value [2] Optimisation on.
3. A START signal is gi v en and parameter 107
Automatic motor tuning is reset to [0] when
AMT has been completed.
Complete AMT:
AMT is completed by gi v ing a RESET signal.
Parameter 108 Stator resistance, Rs is updated
with the optimised value.
Interrupting AMT:
AMT can be interrupted during the optimisation
procedure by gi v ing a STOP signal.
When using the AMT function the following
points should be observed:
- For AMT to be able to define the motor parameters
as well as possible, the correct type plate data for
= factory setting. () = display text [] = value for use in communication via serial communication port
70
x 60. f to be
M,N M,N
.
M,N
[0]
[2]
. As a
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®
VLT 2800 Series
the motor connected to the frequency converter
must be keyed into parameters 102 to 106.
- Alarms will appear in the display if faults arise
during tuning of the motor.
- As a rule the AMT function will be able to measure
the R values for motors that are 1-2 times larger or
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smaller than the frequency converter's nominal size.
- If you wish to interrupt automatic motor tuning,
press the [STOP/RESET] key.
NB!:
AMT may not be performed on motors
connected in parallel, nor may setup changes
be made while AMT is running.
The procedure for AMT controlled from the SLCP:
See section entitled Control unit.
Description of choice:
Select Optimisation on [2] if you want the frequency
converter to perform automatic motor tuning.
108 Stator resistance R
(STATOR RESISTAN)
Value:
0.000 - X.XXX
Depends on choice of motor
Function:
After setting of parameters 102-106 Nameplate data,
a number of adjustments of various parameters is
carried out automatically, including stator resistance
R . A manually entered R
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motor. The shaft performance can be improved by
fine-tuning R and X , see procedure below.
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NB!:
Parameters 108 Stator resistance R
Stator reactance X
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changed if nameplate data has been set.
Description of choice:
R can be set as follows:
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1. Use the factory settings of R
frequency converter itself chooses on the basis
of the motor nameplate data.
2. The value is stated by the motor supplier.
3. The value is obtained through manual
measurements: R can be calculated by measuring
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the resistance R
PHASE-PHASE
terminals. Where R
PHASE-PHASE
Ohms (typical for motors > 5.5 kW, 400 V), a special
MG.28.E9.02 - VLT is a registered Danfoss trademark
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must apply to a cold
and 109
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are normally not to be
which the
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between two phase
is lower than 1-2