Autophasing modes
Several autophasing modes are available (see parameter 21.13).
The turning mode (Turning) is recommended especially with case 1 (see the list
above) as it is the most robust and accurate method. In turning mode, the motor
shaft is turned back and forward (±360/polepairs)° in order to determine the rotor
position. In case 3 (open-loop control), the shaft is turned only in one direction
and the angle is smaller.
Another turning mode, Turning with Z-pulse, can be used if there is difficulty using
the normal turning mode, for example, because of significant friction. With this
mode, the rotor is turned slowly until a zero pulse is detected from the encoder.
When the zero pulse is detected for the first time, its position is stored into
parameter 98.15, which can be edited for fine-tuning. Note that it is not mandatory
to use this mode with a zero pulse encoder. In open-loop control, the two turning
modes are identical.
The standstill modes (Standstill 1, Standstill 2) can be used if the motor cannot be
turned (for example, when the load is connected). As the characteristics of motors
and loads differ, testing must be done to find out the most suitable standstill
mode.
The drive is capable of determining the rotor position when started into a running
motor in open-loop or closed-loop control. In this situation, the setting of 21.13
has no effect.
The autophasing routine can fail and therefore it is recommended to perform the
routine several times and check the value of parameter 98.15.
An autophasing fault (3385) can occur with a running motor if the estimated angle
of the motor differs too much from the measured angle. This could be caused by,
for example, the following:
• The encoder is slipping on the motor shaft
• An incorrect value has been entered into 98.15
• The motor is already turning before the autophasing routine is started
• Turning mode is selected in 21.13 but the motor shaft is locked
• Turning with Z-pulse mode is selected in 21.13 but no zero pulse is detected
within a revolution of the motor
• The wrong motor type is selected in 99.3
• Motor ID run has failed.
Settings and diagnostics
Parameters: 6.21 Drive status word 3 (page 157), 21.13 Autophasing mode (page 258),
98.15 Position offset user (page 535) and 99.13 ID run requested (page 539).
Program features 91
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