VLT ® 2900 Series NB! The max. value equals f M,N x 60. f M,N to be set in parameter 104 Motor frequency, f M,N . When using the AMT function the following points should be observed: - For AMT to be able to define the motor pa- rameters as well as possible, the correct type plate data for the motor connected to the fre- quency converter must be keyed into param- eters 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 S values for motors that are 1-2 times larger or smaller than the frequency converter's nominal size.
Optimisation off (AMT off) [0] Optimisation on (AMT start) [2] - If you wish to interrupt automatic motor tun- ing, press the [STOP/RESET] key. NB! AMT is not possible on VLT 2980-2982. 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 . Automatic motor tuning is an algorithm that measures stator resistance R S without the motor axle turning. This means that the motor is not delivering 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. Programming Select Optimisation on [2] if you want the frequency converter to perform automatic motor tuning. 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 S . As a rule, however, this is not critical. 0.000 - X.XXX Ω AMT is performed as follows: Depends on choice of motor Start AMT:
After setting of parameters 102-106 Nameplate data, a number of adjustments of various parameters is car- ried out automatically, including stator resistance R S . A manually entered R S must apply to a cold motor. The shaft performance can be improved by fine-tuning R S and X S , see procedure below. 1. Give a STOP signal. 2. Parameter 107 Automatic motor tuning is set at value [2] Optimisation on . 3. A START signal is given and parameter 107 Automatic motor tuning is reset to [0] when AMT has been completed. Complete AMT: AMT is completed by giving a RESET signal. Param- eter 108 Stator resistance, Rs is updated with the optimised value. NB!
Parameters 108 Stator resistance R S and 109 Stator reactance X S are normally not to be changed if nameplate data has been set. Interrupting AMT: AMT can be interrupted during the optimisation pro- cedure by giving a STOP signal. R S can be set as follows: = factory setting, () = display text, [] = value for use in communication via serial communication port MG.29.A3.02 - VLT ® is a registered Danfoss trademark 21 107 Automatic motor tuning, AMT (auto motor tun.) Value: Function: Description of choice: 108 Stator resistance RS (STATOR RESISTAN) Value: Function: Description of choice: