Siemens SIMATIC ET 200pro - Page 127

Setting functions
8.5 Motor control
SIMATIC ET 200pro FC-2 converter
Operating Instructions, 04/2015, FW V4.7.3, A5E34257324B AB
127
Function
From the actual speed, the actual motor torque and the frictional torque of the load, the
inverter calculates the total moment of inertia of the load and motor.
Figure 8-18 Overview of the function of the moment of inertia estimator
Calculating the load torque
At low speeds, the inverter calculates the load torque
M
L
from the actual motor torque.
The calculation takes place under the following co
n-
ditions:
•
Speed ≥ p1226
•
Acceleration setpoint < 8 1/s
2
(≙ speed change
480 rpm per s)
•
Acceleration × moment of inertia (r1493) < 0.9 ×
p1560