Siemens Sinamics G110M Operating Instructions Manual page 248

Advanced commissioning
6.17 Motor control
Calculating the moment of inertia
If all of the following conditions are met, the inverter calculates the moment of inertia:
①
•
– The sign of M
– M
②
•
• The inverter has calculated the load torque in at least one direction of rotation.
• Acceleration setpoint > 8 1/s
③
The inverter calculates the load torque again after acceleration.
Moment of inertia precontrol
In applications where the motor predominantly operates with a constant speed, the inverter
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.
248
The rated accelerating torque M
is the same as the direction of the actual acceleration
B
> p1560 × rated motor torque (r0333)
B
speed > p1755
For higher speed changes, the inverter initially
calculates the accelerating torque M
ence between the motor torque M
torque M
L
M = M - M
B M
Moment of inertia J of the motor and load is
obtained from the accelerating torque M
angular acceleration α (α = rate at which the
speed changes):
J = M / α
B
must satisfy the following two conditions:
B
(≙ speed change 480 rpm per s)
2
Distributed converter for SIMOGEAR geared motors
Operating Instructions, 09/2017, FW V4.7.9, A5E31298649B AH
and frictional torque M
R
- M
L R
as differ-
B
, load
M
:
and
B