Siemens SINUMERIK 840D sl Function Manual page 261

2.18 Kneeshaped acceleration characteristic curve
2.18.1 Detailed Description
2.18.1.1 Adaptation to the motor characteristic curve
Function
Various types of motor, particularly stepper motors, have a torque characteristic that is highly
dependent upon speed and shows a steep decrease in torque in the upper speed range. To
ensure optimum utilization of the motor characteristic curve, it is necessary to reduce the
acceleration once a certain speed is reached.
Figure 2-5
1:
n
red
n
max
M
max
M
red
Simulation of torque characteristic
For the purpose of simulating the torque characteristic of the motor characteristic curve, the
machine data:
MD35242 $MA_ACCEL_REDUCTION_TYPE =
can be used to select various types of characteristic curve:
Basic logic functions: Acceleration (B2)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
Torque characteristic curve of a motor with torque characteristic that is highly dependent
upon speed
Torque decrease zone
: Speed above which reduced torque has to be assumed
: Maximum speed
: Max. torque
: Torque at n (corresponds to creep acceleration)
max
2.18 Kneeshaped acceleration characteristic curve
characteristic
Functions
43