Stage 2 of Auto-tuning (ID 1270)
Stage 2 determines the no-load motor current and the motor inertia. The motor rotates at 30%
of rated speed during this stage.
DANGER
Spinning of the Motor
The motor spins during Stage 2 of auto-tuning.
Stay clear of moving parts to avoid death or serious injury.
Ensure that it is acceptable to spin the motor before this test is enabled.
Generally, Stage 2 of auto-tuning requires the motor to be de-coupled from the load. Quadratic
loads, such as pumps and fans, do not require the motor to be de-coupled for Stage 2 auto-
tuning. The control is designed to minimize the errors introduced by such loads.
Data obtained in Stage 2 is used to optimize the operation of the outer loops that control motor
speed and motor ux. The speed and ux loop gains are automatically calculated and saved by
the control.
7.13.2 Spinning Load
The spinning load feature allows the drive to determine the speed of a motor that is already
rotating. This allows the drive to apply output voltages at the same frequency as the rotating
motor and minimize any chance of a speed or torque transient.
When to use Spinning Load
Enable spinning load if any of the following operating modes or features are selected:
• Fast bypass
• Auto-restart (controlled through the auto reset parameters 7120 to 7150 and the SOP)
• Synchronous motor control (SMC and CSMC)
• Closed loop vector control (CLVC)
Note
Characteristics of Spinning Load Operation
Spinning load is disabled with V/Hz and OLTM Control.
Spinning load is only enabled during the fast bypass operation.
With synchronous motors, spinning load is almost instantaneous, i.e. the drive only goes into
a scan mode until ux is established, then the phase locked loop (PLL) locks onto the output
frequency.
Operating the Control
7.13 Drive Tuning
NXGPro+ Control Manual
Operating Manual, A5E50491925A 227
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