In this article, we explore the fundamental questions and considerations that should guide every electrification project, helping teams move beyond assumptions and toward solutions that perform consistently in the toughest scenarios.
Drawing on decades of hands-on expertise, Benny Forsman, an electrification expert with decades of engineering experience and current Business Development Director at Inmotion, shares practical insights into what truly drives optimal system solution selection. His perspective emphasizes a holistic approach, considering not only the motor itself but the entire system, including power electronics and battery characteristics.
Performance Requirements: Firm vs. Negotiable
The foundation of any successful system selection process is a clear understanding of performance requirements, and this starts with collaboration. Electrification professionals and OEM teams must work together to distinguish between non-negotiable performance criteria and those that allow flexibility. For example, in an application such as a pushback tractor, the ability to generate sufficient torque to move the heaviest aircraft is an absolute requirement. This parameter defines the baseline for motor sizing and cannot be compromised.
However, other factors often fall into the “negotiable” category. Consider terrain: will the machine operate exclusively on flat surfaces, or will it encounter inclines? Even a modest slope can significantly influence torque demand and thermal behavior, impacting motor selection. By identifying these variables early, teams can avoid oversizing or undersizing the motor, ensuring both performance and cost efficiency.
This step is about enabling informed trade-offs. When OEMs and electrification experts communicate effectively, they can prioritize what truly matters for the application while maintaining flexibility where possible. This collaborative approach sets the stage for optimized design decisions throughout the electrification project.
Peak vs. Thermal Performance: What Really Drives Sizing
Motor sizing is often approached with a focus on peak performance, how much torque or power the machine can deliver in short bursts. While this is important, it’s only half the story. In many applications, thermal performance becomes the real limiting factor. A motor that can achieve high peak torque for a few seconds may struggle to sustain performance under continuous load if heat management isn’t properly addressed. This is why understanding duty cycles and operating conditions is critical during the specification phase.
Equally important is recognizing that the motor does not operate in isolation. True optimization comes from considering the entire system, including the inverter and power electronics. When these components are sized and tuned together, efficiency improves, thermal stress is reduced, and overall performance becomes more predictable. Treating the motor and inverter as separate entities often leads to suboptimal solutions, either oversized components that inflate costs or undersized ones that compromise reliability.
A holistic approach ensures that every part of the system works in harmony, delivering consistent results across all operating scenarios. This mindset is essential for OEMs and electrification professionals aiming to balance performance, durability, and cost-effectiveness in their projects.
Planning for Real-World Conditions and Edge Cases
Motor performance is often evaluated at nominal battery voltage, but real-world conditions rarely align with this ideal scenario. As the battery discharges, voltage drops, and this can dramatically affect the motor’s ability to deliver critical functions. For instance, can the machine still perform a demanding task when the state of charge is low, and voltage falls below the expected level? Ignoring this question can lead to unexpected performance gaps in the field.
To address this, teams must size the motor for edge cases, not just average conditions. This means considering the minimum voltage at which essential operations must still be possible. Applications like steer-by-wire systems illustrate the risk: when voltage drops, motor speed decreases, potentially compromising safety and functionality. But edge cases go beyond voltage alone, they include scenarios such as operating under maximum payload, climbing steep inclines, or performing emergency maneuvers in extreme temperatures. Each of these conditions can push the motor and inverter to their limits, and if they aren’t accounted for during design, the system may fail when it matters most.
Planning for these worst-case scenarios requires detailed simulations and, ideally, physical testing under controlled conditions. By modeling how the system behaves at low voltage, high load, and varying temperatures, engineers can identify vulnerabilities and make informed design adjustments. This proactive approach ensures that electrified machines remain dependable, even in the most demanding environments.
Temperature and Environmental Factors
Ambient conditions, component operating temperatures, and cooling strategies all play a decisive role in determining whether a motor can sustain its required output. High heat can degrade insulation and reduce efficiency, while extreme cold can affect lubrication and material properties. Ignoring these factors during design can lead to premature failures or inconsistent performance in the field.
To mitigate these risks, comprehensive testing under controlled conditions is essential. This includes validating performance at both high and low temperature extremes, simulating real-world operating environments. Advanced dyno lab testing allows teams to heat or cool components and verify that the system meets its performance targets across the full temperature range. By incorporating these evaluations early, OEMs and electrification professionals can ensure reliability and durability, even in the harshest operating scenarios.
Conclusion: Collaboration for Optimal Electrification Solutions
Selecting the right system solution for an electrification project is a strategic decision that impacts performance, reliability, and cost throughout the equipment’s lifecycle. Success depends on collaboration between OEMs and electrification professionals, ensuring that requirements are clearly defined and edge cases are anticipated. By approaching motor selection as part of a complete system, teams can avoid costly redesigns and deliver solutions that perform consistently under real-world conditions.
Key takeaways for electrification projects:
- Define firm and negotiable requirements early. Identify absolute performance needs (e.g., torque for critical tasks) and clarify where flexibility exists.
- Consider thermal limits, not just peak performance. Continuous operation and heat management often dictate motor sizing more than short bursts of power.
- Optimize the entire system, not individual components. Motor and inverter must be sized and tuned together for efficiency and reliability.
- Plan for voltage variability and edge cases. Ensure essential functions remain possible even at low battery charge or reduced voltage.
- Validate performance under temperature extremes. Comprehensive testing in controlled environments prevents surprises in harsh operating conditions.
Electrification is transforming the industry, and with the right questions and collaborative mindset, it can unlock new levels of performance, sustainability, and innovation. Teams that embrace this holistic approach will be best positioned to lead in the next generation of off-highway and industrial solutions.
Author: Francesco Patroncini