1. Introduction: The Need for Modernization of Industrial Drives
In modern industrial production, the efficiency, reliability and adaptability of equipment are critical to ensure competitiveness. The fixed-speed drives still widely used often fall short of today's requirements for energy efficiency, precise process control, and reduced operating costs. Outdated systems can lead to significant overspending of energy, increased wear and tear of mechanical components, frequent unscheduled shutdowns, and complexity of integration into modern automation systems. In addition, growing regulatory requirements, such as EU eco-design directives and national energy management standards (eg DSTU EN ISO 50001:2018), encourage enterprises to implement energy-saving technologies.
Modernization of drives through the introduction of variable frequency drives (VFD) or VFD (Variable Frequency Drive) allows to achieve a significant reduction in electricity consumption, increase the accuracy of control of technological processes and increase the overall operational efficiency. This technical manual examines the key aspects of the transition to the PRC, focusing on the economic benefits and practical recommendations for Ukrainian industrial enterprises.
2. Evaluation of Existing Systems: Criteria for Retrofit
A thorough evaluation of existing drive systems is necessary before making a decision to upgrade. This will make it possible to identify the most critical areas and justify investments. The table below presents the key criteria to consider:
| Evaluation Criterion | Description | Identified Problems (Example) |
|---|---|---|
| Energy consumption | Actual electricity consumption compared to optimal. | The 30 kW engine works at full power, although the load is variable (pump, fan), overspending is up to 35%. |
| Reliability and MTBF | Failure frequency and mean time to failure (MTBF) of mechanical components (reducers, bearings). | MTBF of the drive mechanism is 8000 hours due to direct start shock loads. |
| Management Quality | Accuracy of maintaining technological parameters (pressure, flow, speed, temperature). | Regulation of the flow of liquid by the valve, and not by the speed of the pump, which leads to pressure fluctuations of ±0.5 bar. |
| Operating Expenses | Costs for maintenance, repairs, spare parts, personnel. | Annual costs for repairing mechanical transmissions and replacing seals exceed 1500 EUR for one unit. |
| Integration into ATS TP | The possibility of integrating the drive into centralized control systems. | Lack of interfaces for data exchange with DCS/SCADA, manual control. |
| Noise and Vibration Level | Contamination of the working environment with noise and vibration. | The noise level exceeds 85 dB at a distance of 1 m from the drive. |
3. Modern Alternatives: Comparison of Technologies
The transition from direct start to control with the help of PRC is a fundamental step to improve efficiency. Here is a comparison of a typical solution with a fixed speed and a modern solution with a CDP:
| Parameter | Existing System (Example: Asynchronous motor, direct start) | Modern System (Example: Asynchronous motor + Heidenhain 355880-30 VFD) |
|---|---|---|
| Speed Control | Fixed, 100% nominal. | Smooth, 0 to 150% of rated (depending on motor and VFD). |
| Energy efficiency (IE Class) | IE1/IE2 (for older engines). | IE3/IE4 (for modern motors) combined with VFD optimization. The efficiency of the VFD Heidenhain 355880-30 is 98.5% at rated load. |
| Starting Currents | High (up to 7-8 times the rated current), shock loads. | Low, smooth start/stop. Starting currents are limited to 1.5-2 times the nominal current. |
| Control Accuracy | Low, only discrete on/off. Performance adjustment by throttling or shifting gears. | High, ±0.1% of the set speed. Precise control of pressure, flow, temperature. |
| Wearing Mechanics | High, frequent repairs of couplings, gearboxes, bearings. | Significantly reduced, increasing MTBF up to 2-3 times. |
| Diagnosis | Limited, visual inspection. | Advanced, current, voltage, temperature, frequency monitoring, fault diagnosis. |
| Integration | Difficult or impossible without additional modules. | Simple integration via industrial networks (Modbus RTU, Profibus, EtherCAT). Heidenhain 355880-30 supports these protocols. |
| Noise and Vibration | Tall. | Significantly reduced. |
4. Calculation of Return on Investment (ROI)
A detailed ROI calculation is key to justifying a modernization project. Consider an example for a pumping station with a 30 kW motor.
Output Data:
- Engine power: P = 30 kW
- Operating hours per year: H = 8000 hours
- Cost of electricity: Ce = 0.15 EUR/kWh (industrial average for Ukraine)
- Average energy savings from the implementation of PRC: Es = 25% (typical for pump and fan applications)
- The cost of one VFD (for example, Heidenhain 355880-30 or similar): VFDcost = 3500 EUR
- The cost of installation and commissioning: Icost = 1500 EUR
- Annual maintenance costs of the old system: Mold = 1200 EUR (replacement of couplings, bearings, repair)
- Annual maintenance costs of the new system: Mnew = 400 EUR (scheduled maintenance of the PRP)
- Equipment downtime cost: Dcost = 500 EUR/hour
- Reduction of downtimes thanks to PRP: Rdowntime = 20 hours/year (due to smooth start-up, load reduction)
Calculations:
- Annual energy consumption of the old system:
Cold = P * H * Ce = 30 kW * 8000 h * 0.15 EUR/kWh = 36000 EUR/year - Annual energy savings:
Se = Сold * Es = 36000 EUR/year * 0.25 = 9000 EUR/year - Savings on maintenance:
Sm = Mold - Mnew = 1200 EUR - 400 EUR = 800 EUR/year - Savings from reduced downtime:
Sd = Dcost * Rdowntime = 500 EUR/hour * 20 hours/year = 10000 EUR/year - Total annual savings:
Stotal = Se + Sm + Sd = 9000 + 800 + 10000 = 19800 EUR/year - Total investment costs:
Itotal = VFDcost + Icost = 3500 EUR + 1500 EUR = 5000 EUR - Payback Period:
PP = Itotal / Stotal = 5000 EUR / 19800 EUR/year ≈ 0.25 years (approximately 3 months)
Thus, the investment in the modernization of drives pays off in an exceptionally short period of time. Even if the "old system still works", its hidden cost due to poor efficiency, frequent breakdowns and limited control far exceeds the initial cost of the upgrade. Given the rise in energy prices, this payback period may be even shorter. It also meets the requirements of energy audits and DSTU EN ISO 50001:2018 standards.
5. Implementation Roadmap: A Phased Approach
The effective implementation of HRC requires careful planning to minimize production disruptions. A phased approach is recommended:
Planning and Audit (1-2 weeks)
- Detailed audit: Determination of all drives to be upgraded, their current operating parameters, loads and duration of operation.
- Feasibility study: Carrying out ROI calculations for each drive or group of drives.
- Equipment selection: Consultation with suppliers (e.g. UNITEC-D) on selection of optimal PMCs such as Heidenhain 355880-30 and associated equipment.
- Project documentation: Development of connection schemes, control algorithms, specifications.
Purchase (2-4 weeks)
- Orders: Placement of orders for control units, cables, filters, sensors, control cabinets. UNITEC-D ensures the supply of certified equipment.
- Logistics: Organization of equipment delivery to the object.
Installation and Connection (1-3 days per unit of equipment)
- Dismantling: Neat dismantling of existing components.
- CRP installation: Installation of control cabinet, CRP, connection of power and control cables in compliance with electrical safety standards (PUE, DSTU EN 60204-1:2018).
- Grounding and shielding: Provide adequate grounding and shielding to minimize electromagnetic interference.
Commissioning Works and Commission Service (1-2 days per equipment unit)
- Preliminary checks: Checking the correctness of connections, insulation resistance.
- Setting the parameters of the CRP: Entering the nominal parameters of the motor, setting the vector control (if supported), configuring the PID controllers.
- Testing: Idle start, start under load, check of operation in different modes.
- Integration into ATS TP: Setting up data exchange with a higher level of control.
6. Technical Challenges and Ways to Solve Them
Certain technical difficulties may arise during the implementation of the ChRP, which require a qualified approach:
- Electromagnetic Compatibility (EMC): RFCs generate high-frequency interference. Solution: use of EMC filters, shielded cables, separate laying of power and control cables according to DSTU EN 61000-6-2:2015 and DSTU EN 61000-6-4:2015.
- Harmonics in the Network: High harmonics can lead to overheating of transformers and reactive power compensators. Solution: use of chokes, active harmonic filters, multi-pulse rectifiers.
- Motor Compatibility: Older motors may not be designed to operate with high switching frequency of PWM PWM, which can lead to overheating and accelerated insulation wear. Solutions: check motor insulation class, use dU/dt output filters or sine filters, use motors designed to work with PRC (for example, F or H insulation).
- Resonance and Vibration: Some mechanical systems may have their own resonant frequencies that coincide with the frequencies generated by the FRP. The solution: the function of passing resonant frequencies in the settings of the CRP, balancing of mechanical parts.
- Voltage Drops: Sensitivity of the PRC to voltage drops in the industrial network. Solution: use of network chokes, capacitors, uninterruptible power supply systems for control electronics.
7. Example: Modernization of the Technological Pump Drive
"Before" situation
At one of the chemical enterprises of Ukraine, in the fertilizer production workshop, a centrifugal pump for pumping reagents was operating. The 45 kW engine operated at a fixed speed of 1500 rpm. Performance regulation was carried out by throttling the pressure pipeline using a valve. This resulted in significant energy losses, pump cavitation and frequent seal and bearing failures. The average number of downtimes per year was 50 hours, the cost of one repair was 1,500 EUR. Annual energy consumption is 250,000 kWh. MTBF of the pump unit was 7000 hours.
Situation "After"
A decision was made to modernize the drive by installing a Heidenhain 355880-30 control unit and integrating it into the existing automatic control system. ChRP made it possible to smoothly adjust the speed of rotation of the pump in accordance with the needs of the technological process. As a result:
- Energy consumption: Decreased by 30%, to 175,000 kWh/year (savings of 75,000 kWh/year).
- Downtime: Reduced to 10 hours per year (due to soft start and no cavitation).
- MTBF: Increased to 18,000 hours (reduced seal and bearing wear).
- Control accuracy: The pressure in the pipeline is maintained with an accuracy of ±0.05 bar instead of ±0.5 bar.
- Product quality: Stabilizing the supply of reagents led to an increase in the quality of the final product.
The total annual energy savings, reduced downtime and lower maintenance costs amounted to around 17,000 EUR/year. Investment costs (CRP, installation, commissioning) amounted to EUR 7,000. The payback period is less than 5 months.
8. Commission Service and Validation
After installation and commissioning, a commissioning and validation stage is required. This confirms the compliance of the system with the design parameters and functional requirements.
- Functional testing: Checking of the operation of the CHRP in all specified modes, including emergency stops, protections, operation with external signals.
- Measurement of parameters: Measurement of electricity consumption (before and after), pressure, flow, temperature, vibration. Use of certified measuring devices.
- Integration testing: Checking the correctness of data exchange with ACS and SCADA systems.
- Protocols: Preparation of test protocols and commissioning.
- Education of personnel: Training for operational and service personnel on working with new equipment.
- Certification: Ensuring compliance of the established PRC with CE standards and obtaining, if necessary, UkrSEPRO certification for operation in Ukraine.
Compliance with the validation process of the DSTU ISO/IEC 17025 standard is a confirmation of the reliability of the obtained results.
9. Conclusion
Modernization of drive systems with the help of frequency converters is not just a technical update, but a strategic investment that provides a significant increase in energy efficiency, reliability, and precision in the management of production processes. Short payback times due to energy savings, lower maintenance costs and less downtime make this technology critical to today's industry. The UNITEC-D company offers a full range of solutions - from the supply of modern PRPs, such as the Heidenhain 355880-30, to comprehensive engineering and support at all stages of implementation. For detailed information on the product range and retrofit solutions, visit the UNITEC-D E-Catalog.
10. Links
- DSTU EN ISO 50001:2018 (ISO 50001:2018, IDT) Energy management systems. Application requirements and guidelines.
- DSTU EN 50598-2:2016 (EN 50598-2:2014, IDT) Efficiency of variable speed electric drive systems. Part 2. General requirements for the design of efficient systems.
- DSTU EN 60204-1:2018 (EN 60204-1:2018, IDT) Machine safety. Electrical equipment of machines. Part 1. General requirements.
- DSTU EN 61000-6-2:2015 (EN 61000-6-2:2005, IDT) Electromagnetic compatibility (EMC). Part 6-2. General standards. Interference resistance for an industrial environment.
- DSTU EN 61000-6-4:2015 (EN 61000-6-4:2007, IDT) Electromagnetic compatibility (EMC). Part 6-4. General standards. Emission standard for industrial environments.
- DSTU ISO/IEC 17025:2019 (ISO/IEC 17025:2017, IDT) General requirements for the competence of testing and calibration laboratories.
- EU Directive 2009/125/EC (Ecodesign Directive) establishing a framework for establishing ecodesign requirements for energy-consuming products.
- Technical documentation and manuals for the operation of the Heidenhain 355880-30 CPP.
