Power calculation of servomotors: inertia ratio, moment curves and optimization of dynamic compliance

Introduction: Engineering requirement and criticality of the topic for manufacturing reliability

The correct power calculation of servo motors is critical to ensure the reliability, productivity and economic efficiency of industrial systems. Servo motors perform functions that require high control accuracy, quick response and stable operation under various loads. Miscalculations can lead to unplanned shutdowns, component wear, and increased maintenance costs. This article discusses a methodology for selecting servo motors that meets standards including DSTU, EN, ISO and ensures optimal dynamic compliance.

Fundamental principles: physics, mechanics and electrical engineering

Servomotors work on the basis of the principle of matching the inertia of the load and the motor. This is reflected in the moment of inertia equation, which defines the relationship between motor torque and load inertia:

J = I * α

where J is the moment of inertia, I is the load inertia, α is the angular acceleration. If the load's inertia exceeds the motor's torque, lag occurs, resulting in incorrect positions and loss of accuracy.

Moment curves are a key element in determining dynamic compliance. They reflect the dependence of the moment on the speed, which determines the ability of the engine to perform various operations. The curves have an appearance that depends on the type of motor: DC, AC, or AC with vector control.

Technical characteristics and standards

Servomotors must meet the following standards:

• ISO 281 - standardized methods for measuring torque and speed
• DIN 51825 — standards of moment dependence on speed
• IEC 60947-2 — requirements for electromagnetic switches for servomotors
• ISO 10216-1 is a standard for requirements for electrical equipment in conditions of high humidity
• EN 60034-1 is a standard for measuring the power and efficiency of engines

In addition, servomotors must be certified by CE and UkrSEPRO to ensure compliance with operating conditions in Ukraine.

Selection and calculation of capacity: criteria and formulas

To select a servomotor, the following steps must be performed:

1. Determination of the moment of inertia of the load
2. Calculation of the maximum moment from the load
3. Selection of a motor with a torque exceeding the maximum load
4. Motor selection with appropriate torque curves

The moment of inertia of the load is calculated according to the formula:

J = Σ (m * r²)

where m is the mass of the element, r is the distance to the axis of rotation. The maximum load moment is determined by the formula:

T = F * r

where F is the force, r is the moment radius. Engine power is determined by the formula:

P = T * ω

where ω is the angular velocity. The motor should have a torque that exceeds the maximum load by 20-30%.

Setup and implementation: practical recommendations

Correct installation and adjustment of the servo motor is critical to its efficient operation. Here are the main recommendations:

• Use appropriate cables and busbars for power transmission
• Check the clearances and distances between the motor and the load
• Install controls and adjustments
• Perform testing after installation
• Ensure proper cooling

The use of specialized equipment, such as UNITEC-D servo motors, ensures reliability and high precision.

Violation and analysis of reasons for elimination

Servo motors can fail for a variety of reasons, including:

• High load moment
• Incorrect setting
• Insufficient cooling level
• Damaged cable or bus
• High ambient temperature

Determining the reasons for knocking out can be done by analyzing visual signs, such as:

• Increase in engine temperature
• Changing the color of the cables
• Increase in vibration
• Incorrect behavior in the management system

Using sensory analysis techniques such as visual inspection and temperature measurement is an effective way to determine the cause.

Maintenance forecasting and condition monitoring

Maintenance forecasting and condition monitoring are performed using the following technologies:

• VIBRATION ANALYSIS — measurement of vibration to detect deviations
• THROUGH-PROBING — temperature and voltage measurement
• ULTRASONIC TESTING — detection of defects in working conditions
• CONDITION MONITORING SYSTEMS — real-time monitoring systems
• AI-BASED PREDICTIVE MAINTENANCE — use of artificial intelligence for data analysis

Using these methods can reduce unplanned shutdowns and repair costs.

Comparison table: options for servo motors

Conclusion: Selection of servomotors from UNITEC-D

The correct calculation and selection of servomotors requires careful analysis of technical characteristics, compliance with standards and the use of appropriate maintenance methods. UNITEC-D servomotors ensure reliability, accuracy and high efficiency, compliance with DSTU, EN, ISO standards and CE, UkrSEPRO certification. Choose the servo motor that meets your requirements and cut out all the unnecessary costs.

Sources

• ISO 281 - Standards for measuring torque and speed
• DIN 51825 — Standards for torque and speed requirements
• IEC 60947-2 — Requirements for electromagnetic switches
• EN 60034-1 — Engine power and efficiency requirements
• ISO 10216-1 — Requirements for electrical equipment in conditions of high humidity

Go to the UNITEC-D catalog to select the right servo motor for your production.