Define The Load Case, Calculate The Maximum Load Torque And Determine The Motor - Siemens SIMOTICS S-1FK2 Configuration Manual

Configuration
5.2 Configuring procedure
5.2.3 Define the load case, calculate the maximum load torque and determine the
motor
The motors are defined bases on the motor type-specific limiting characteristic curves.
The limiting characteristic curves describe the torque or power curve over the speed.
The limiting characteristic curves take the limits of the motor into account on the basis of the DC-
link voltage. The DC-link voltage is dependent on the line voltage.
M_max
S1
Figure 5-1
Procedure
1. Determine the load which is specified by the application.
Use different characteristics for the different loads.
The following operating scenarios have been defined:
– Duty cycle with constant ON duration
– Free duty cycle
2. Determine the characteristic torque and speed operating points of the motor for the defined
load.
3. Calculate the acceleration torque of the motor.
Add the load torque and the acceleration torque. to obtain the maximum required torque.
4. Verify the maximum motor torque with the limiting characteristic curves of the motors.
The following criteria must be taken into account when selecting the motor:
– Compliance with the dynamic limits
– Compliance with the thermal limits
You have specified a motor.
68
Curve of the maximum torque
S1 characteristic
Limit characteristics for synchronous motors
All torque-speed points of the load must be below the relevant limiting characteristic
curve.
At average speed, the effective motor torque must be below the S1 characteristic
(continuous operation) during the load.
1FK2 Synchronous Motors for SINAMICS S120
Configuration Manual, 02/2022, A5E46927724B AD