Electrification promises cleaner, more efficient off-highway equipment—but the path to success is anything but uniform. Each application comes with unique operating patterns, load demands, and environmental conditions that directly impact system design. This is where duty cycles become essential.
By analyzing how machines actually work in the field, manufacturers can tailor battery capacity, motor performance, and energy management strategies to deliver optimal results. In this article, we explore why duty cycles matter and how they shape the future of electrified off-highway solutions.
Performance Requirements Drive Selection
When it comes to motor selection, speed and torque are the foundation of every decision. These two parameters define how the machine will behave under real-world conditions. Speed determines how quickly the system can complete its tasks, while torque measures its ability to overcome resistance, whether that’s moving a heavy load, climbing a steep incline, or operating in challenging terrain.
Consider two examples:
- A compact utility vehicle designed for landscaping may prioritize higher speed for efficient travel across large areas, with moderate torque for light towing.
- A forklift in a warehouse needs strong torque at low speeds to lift heavy pallets and maneuver precisely in tight spaces.
In both cases, oversizing the motor might seem like a safe bet, but it introduces significant drawbacks. A larger motor adds weight, complicates packaging, and increases costs, not only for the motor itself but also for the controller and supporting components. This is why engineers aim for the smallest motor that still meets the required speed and torque profile. From a cost perspective, the relationship is clear: motor cost scales primarily with torque capability, while controller cost is driven by power rating. For instance, doubling torque capacity from 50 Nm to 100 Nm can add several hundred dollars to the motor price, even if speed requirements remain unchanged. Oversizing also impacts the controller, which must handle higher currents, and further increasing system cost. Beyond price, oversizing can also reduce efficiency, leading to wasted energy and shorter battery life. Critical factors in electrified applications.
This is why precise sizing based on performance requirements is important. A well-matched motor ensures cost efficiency without sacrificing reliability, while avoiding oversizing helps maintain packaging flexibility and overall system optimization. In electrification projects, where margins and energy budgets can be tight, these considerations can make the difference between a competitive solution and an over-engineered system.
Brushless vs. Induction: Efficiency and Battery Strategy
Motor technology is deeply connected to the energy storage system and the overall design philosophy of the vehicle. In applications powered by lead-acid batteries, energy density is relatively low, but the cost of adding extra capacity is modest. This makes it feasible to compensate for a less efficient motor by simply oversizing the battery pack. For example, a slow-moving industrial cart with ample space can afford a heavier battery and still meet operational requirements without major penalties. The scenario changes dramatically with lithium-ion battery systems, which dominate modern electrification projects. These batteries offer high energy density and fast charging, but they come at a premium cost and impose strict packaging constraints. Every watt-hour becomes valuable, and inefficiencies quickly translate into lost range and reduced uptime. Here, the choice of motor technology becomes critical.
Brushless permanent magnet motors address this challenge by delivering superior efficiency across a wide operating range. Their design minimizes electrical and magnetic losses, ensuring that more of the stored energy is converted into useful work. This efficiency advantage compounds in applications with frequent acceleration and braking, where regenerative recovery plays a major role. For OEMs, the benefits are tangible: longer operating time between charges, reduced downtime, and optimized utilization of expensive battery packs.
The Role of Energy Management in Modern Electrification
Energy management is one of the most critical aspects of electrified vehicle design, and motor efficiency plays a central role in this equation. Every joule stored in the battery is a finite resource, and how effectively it is converted into mechanical work determines not only performance but also operating costs and uptime. In modern electrification projects, this efficiency challenge is amplified by duty cycles that involve frequent acceleration, deceleration, and regenerative braking.
Regenerative braking is often seen as a way to “recover” energy, but the reality is more complex. When a motor operates inefficiently, energy losses occur twice: first during propulsion and then during recovery. For example, if a motor has a 90% efficiency during acceleration and 80% during regeneration, the compounded loss means only 72% of the original energy is effectively reused. Over hundreds of cycles per day, this inefficiency translates into significant wasted energy, shorter range, and more frequent charging intervals.
This is why high-efficiency motor technologies, such as brushless PM motors, are increasingly favored in lithium-ion systems. Their ability to minimize electrical and magnetic losses ensures that more energy is preserved throughout the cycle. In applications like material handling, where uptime directly impacts productivity, even a 5–10% improvement in energy efficiency can result in hours of additional operating time per charge. For off-highway vehicles with demanding duty cycles, these gains are even more pronounced, reducing downtime and extending service intervals.
Beyond the motor itself, energy management is a system-level discipline. It involves optimizing controller algorithms, thermal management, and regenerative braking strategies to ensure that every component contributes to overall efficiency. OEMs that prioritize this holistic approach not only improve vehicle performance but also reduce total cost of ownership, a key differentiator in competitive markets.
Finding the Sweet Spot for Your Application
Selecting the right motor is ultimately about finding the optimal balance between performance, efficiency, and cost. While technical specifications provide clear boundaries, real-world applications often fall into gray areas where multiple options seem viable. This is where engineering judgment and system-level thinking become essential.
The guiding principle is simple: choose the smallest motor that meets your speed and torque requirements without compromising reliability. Oversizing may appear to offer a safety margin, but it introduces unnecessary weight, higher component costs, and reduced energy efficiency. Conversely, undersizing can lead to thermal stress, accelerated wear, and premature failure. The sweet spot lies in precise sizing, supported by accurate duty cycle analysis and realistic load profiles. In many cases, investing slightly more in a high-efficiency motor pays dividends over the vehicle’s lifetime.
For example, a brushless PM motor may cost a few hundred dollars more than an induction motor, but the savings in energy consumption, reduced charging downtime, and extended battery life often outweigh the initial premium. In applications where uptime is critical, such as material handling or off-highway equipment, these gains translate directly into productivity and lower total cost of ownership.
Ultimately, motor selection is a strategic choice that impacts the entire electrification system. OEMs that approach this process with a focus on performance optimization and energy management will deliver solutions that meet today’s efficiency standards and remain competitive in the evolving landscape of electrified machinery of tomorrow.
How Inmotion Provides Comprehensive System Solutions
Inmotion’s portfolio is structured to cover a wide range of electrification needs, offering not just motors but complete subsystems that integrate seamlessly with advanced controllers and power electronics. The lineup includes four primary motor families—ASM, XPM, RSM, and GSM—each designed for distinct performance requirements, from the compact ASM to the high-power GSM. By pairing these motors with Inmotion’s inverter and converter solutions, OEMs gain optimized efficiency, precise control, and simplified integration for demanding off-highway applications.
- ASM: A compact, high-efficiency PMAC motor for systems operating between 12V and 120V, delivering 600 W to 2 kW. Its permanent magnet design supports both motor and generator modes, making it ideal for servo, auxiliary, and light traction applications with limited constant power speed ranges. When combined with Inmotion controllers, ASM systems deliver smooth torque control and enhanced safety features.
- XPM: A versatile IPM motor delivering 2 to 11 kW at 24V to 96V. Built for hydraulic pumps, direct-drive systems, and light traction, it combines high efficiency with robust housing for durability in mobile applications. Integrated with Inmotion controllers, XPM solutions offer advanced diagnostics and field-oriented control for maximum performance.
- RSM: A high-performance motor for hydraulic pump applications in battery-powered and hybrid vehicles. Operating between 36V and 96V, it provides 3 to 15 kW and features Sin/Cos feedback for precise control, plus a flexible mechanical interface for easy integration. Paired with Inmotion controllers, RSM systems enable dynamic response and optimized energy use in demanding duty cycles.
- GSM: A compact generator designed for hybrid systems, delivering 14 to 24 kW of continuous power at 24V to 80V. Built with PMAC technology and SAE5 compatibility, it converts mechanical energy into DC power for battery systems, offering maintenance-free operation and integrated thermal protection. Inmotion controllers ensure stable power conversion and system-level safety monitoring.
Power Electronics for Complete Subsystems
- DCC3 Converter: The third-generation DC/DC converter optimized for high-voltage electric and hybrid vehicles. It achieves 96+% efficiency in a rugged design, retaining proven features while improving performance for demanding off-road environments.
- ACH3 Inverter: A flexible inverter family for traction and generator applications in hybrid or battery-powered vehicles. Available in multiple voltage and power configurations, ACH3 meets industry standards for cybersecurity, functional safety, and electrical safety, ensuring reliability without maintenance. Integrated with ZAPI Group’s software platform, it offers customizable vehicle functions for advanced control.
- APS3 Steering Controller: The third-generation Advanced Power Steering controller engineered to meet European functional safety standards. APS3 interfaces with various steering input devices and motor types, operating as a standalone system or within a CANopen-based architecture. Ideal for a wide range of vehicle applications, including Class 1–3 lift trucks.
Author: Francesco Patroncini