Siemens SIMOTICS M-1PH1, Руководство по эксплуатации оборудования

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Configuration
7.2 Specifying the duty cycle
1PH1 main motors
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Equipment Manual, 09/2021, A5E51077676A-AA
Free duty cycle
The figure below shows a load duty cycle that defines the characteristics of the speed and
torque of the motor with respect to the time.
A load torque is specified for each time period. In addition to the load torque, the average
load moment of inertia and motor moment of inertia must be taken into account for
acceleration. It may be necessary to take into account a frictional torque that opposes the
direction of motion.
If a gearbox has been mounted, in determining the load and acceleration torque required by
the motor, the gear ratio and the gear efficiency must be considered. A higher gear ratio
increases positioning accuracy in terms of encoder resolution. For any given motor encoder
resolution, as the gear ratio increases, the resolution of the machine position to be detected
increases.
Permissible motor torque
Once the application has been defined and specified, the maximum motor torque is
calculated. Generally, the maximum motor torque is required during acceleration. The load
torque and the torque required to accelerate the motor are added.
The maximum motor torque is then verified with the limiting characteristic curves of the motor.
The following criteria must be taken into account when you select the motor:
• The dynamic limits must be adhered to, that is, all speed-torque points of a certain load
event must lie below the relevant limiting characteristic curve.
• The thermal limits must be adhered to, that is, the effective motor torque at the average
motor speed resulting from the duty cycle must lie below the S1 characteristic curve
(continuous duty). The effective value of the motor current within a duty cycle must be
less than the rated motor current.
• In the field-weakening range, the permissible motor torque is restricted by the voltage
limit characteristic (stability limit).
Note
Rated pulse frequency
The rated pulse frequency of the 1PH1 motors is 4 kHz. Operation of the motors with a
rated pulse frequency of less than 4 kHz is not permitted.