Siemens SINAMICS G115D Operating Instructions Manual page 272

Advanced commissioning
6.18 Motor control
If all of the following conditions are met, the converter calculates the moment of inertia:
• ① The rated accelerating torque M
– The sign of M
– M
• ② speed > p1755
• The converter has calculated the load torque in at least one direction of rotation.
• Acceleration setpoint > 8 1/s
③ The converter calculates the load torque again after acceleration.
Moment of inertia precontrol
In applications where the motor predominantly operates with a constant speed, the converter
can only infrequently calculate the moment of inertia using the function described above.
Moment of inertia precontrol is available for situations such as these. The moment of inertia
precontrol assumes that there is an approximately linear relationship between the moment of
inertia and the load torque.
Example: For a horizontal conveyor, in a first approximation, the moment of inertia depends
on the load.
The relationship between load torque and torque is saved in the converter as linear
characteristic.
• In a positive direction of rotation:
Moment of inertia J = p5312 × load torque M
• In a negative direction of rotation:
Moment of inertia J = p5314 × load torque M
You have the following options to determine the characteristic:
• You already know the characteristic from other measurements. In this case, you must set
the parameters to known values when commissioning the system.
• The converter iteratively determines the characteristic by performing measurements while
the motor is operational.
Activating the moment of inertia estimator
The moment of inertia estimator is deactivated in the factory setting. p1400.18 = 0,
p1400.20 = 0, p1400.22 = 0.
If you performed the rotating measurement for the motor identification during quick
commissioning, we recommend leaving the moment of inertia estimator deactivated.
270
is the same as the direction of the actual acceleration
B
> p1560 × rated motor torque (r0333)
B
must satisfy the following two conditions:
B
(≙ speed change 480 rpm per s)
2
+ p5313
L
+ p5315
L
Operating Instructions, 12/2020, FW V4.7 SP13, A5E48681219B-002
SINAMICS G115D distributed drive