Baldor VS1STS Series, Installation & Operating Manual, Page: 32 / 74

6-4 Using the Keypad MN767S
6.7 Motor Auto tuning
The VS1STS uses a sophisticated Voltage Vector Control Method as the factory default setting to ensure best possible
motor operation. This control method requires the VS1STS to carry out an auto tune to measure certain motor parameters
prior to operation, to ensure this function operates correctly, and reduce the risk of nuisance tripping.
While the auto tune procedure does not drive or spin the motor, the motor shaft may still turn. It is not normally necessary
to uncouple the load from the motor; however the user should ensure that no risk arises from the possible movement of the
motor shaft.
6.7.1 Auto tune after Factory Reset or from Factory Set Parameters
Following a factory reset (See Section 6.3), the correct data from the motor nameplate should be entered in P1-01 (Motor
Rated Voltage), P1-02 (Motor Rated Current) and P1-03 (Motor Rated Frequency). Providing that P1-02 is adjusted from the
factory default setting, the drive will automatically carry out an auto tune on the motor the first time it is enabled. During the
auto tune, the display will show Auto-t. The test procedure may take several minutes to complete depending on the motor.
Once the auto tune is completed, the drive will operate as normal, and no further auto tuning will be required unless the
motor or drive control mode is changed (P4-01).
6.7.2 User Selected Auto tune
The user can program the drive to carry out an auto tune if required, as follows:
Ensure the motor nameplate values are correctly entered as described above.
Set P1-14 = 101 to allow access to Parameter Groups 2, 3 and 4.
Set P4-02 = 1 and press the button.
The auto tune will begin immediately when P4-02 is set to 1, and no external enable signal is required. During the auto tune
procedure, the motor shaft may turn. It is not normally necessary to uncouple the load from the motor; however the user
should ensure that no risk arises from the possible movement of the motor shaft.
6.8 Operating in Sensorless Vector Speed Control Mode
The VS1STS can be programmed by the user to operate in Sensorless Vector mode, which provides enhanced low speed
torque, optimum motor speed regulation regardless of load and accurate control of the motor torque. In most applications,
the default Voltage Vector control mode will provide adequate performance, however if Sensorless Vector operation is
required, the following procedure should be followed:
Ensure the motor nameplate values are correctly entered in P1-01 (Motor Rated Voltage), P1-02 (Motor Rated Current) and
P1-03 (Motor Rated Frequency)
Set P1-14 = 101 to allow access to parameter groups 2, 3 and 4.
The Motor Rated Power Factor from the motor nameplate MUST be entered in P4-05. If this data is not available, consult the
motor manufacturer for guidance.
Set P4-01 = 0 to select Sensorless Vector Speed Control.
Set P4-02 = 1 to carry out an motor auto tune.
Parameters P4-03 and P4-04 have a significant effect on the behavior of the motor when operating in vector mode.
The auto tune will begin immediately when P4-02 is set to 1, and no external enable signal is required. During the auto tune
procedure, the motor shaft may turn. It is not normally necessary to uncouple the load from the motor; however the user
should ensure that no risk arises from the possible movement of the motor shaft.
6.9 Sensorless Vector Torque Control Mode
For applications which require the drive to control motor torque as opposed to motor speed, the drive can be programmed
to operate in Torque Control mode. When operating this way, the drive internal ramp times (P1-10 and P1-11) are disabled
except during starting and stopping.