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The Tesla Cybertruck‘s Cyberbeast variant isn’t just a statement in design; it’s a mechanical powerhouse. Boasting an incredible 845 horsepower through a unique three-motor setup, the Cyberbeast offers insights into Tesla’s evolving motor design strategy. Munro & Associates recently completed a detailed teardown of these motors, revealing engineering choices that balance cost, performance, and durability. Here’s what automotive engineers, EV enthusiasts, and investors need to know.
Cyberbeast Drive Unit Overview
Up front, the Cyberbeast uses a permanent magnet (PM) motor integrated into a drive unit, which includes a gear mechanism and an inverter neatly packaged at the end. This layout reduces crash exposure, improving safety. In the rear, two symmetrical induction motors each independently drive a rear wheel, with their inverters mounted close by for compact packaging and efficiency.
Tesla’s decision to mix PM and induction motors strategically optimizes range and performance. The front PM motor handles efficient cruising, while the rear induction motors kick in during heavy acceleration or challenging terrain.
Advancements in Stator and Rotor Design
A major design shift is the use of hairpin windings in the PM motor’s stator, moving away from Tesla’s older woven designs. This architecture, similar to that seen in 800V motors like Kia’s, improves efficiency by reducing electrical losses. Eight hairpins per slot maximize power delivery while minimizing heat buildup.
Interestingly, Tesla engineered the PM and induction stators with the same outer diameter, suggesting shared tooling. This strategy lowers production costs and simplifies assembly lines — a hallmark of Tesla’s lean manufacturing ethos.
However, Munro’s team noted differences in contact sizes between the motors, hinting at distinct internal optimizations for power handling.
Magnet Design: Room for Improvement
While most of Tesla’s Cyberbeast innovations impressed, the use of monoblock magnets inside the PM rotor raised concerns. Traditional segmented magnets reduce eddy current losses, improving efficiency and range. Monoblocks, while cheaper, suffer higher losses and generate more heat.
To combat this, Tesla exposed parts of the rotor to allow direct oil cooling — a clever solution, but not without tradeoffs. Munro recommends Tesla revisit segmented magnet designs. Despite higher initial costs, segmenting could enhance range, lower battery drain, and boost long-term system efficiency — vital for EVs expected to last half a million miles or more.
Clever Bearing Assembly Enhancements
Another standout innovation involves the bearing assembly. Typically, bearings need a tight fit to prevent the outer race from spinning, but tight fits complicate assembly. Tesla solved this by placing a spring-loaded pin in the bearing pocket and adding a slight dent on the bearing’s outer race. If the bearing starts to rotate, it catches on the pin, preventing damage.
This elegant, low-cost solution exemplifies Tesla’s lean design philosophy — solving critical problems without adding unnecessary complexity.
Rear Motor Cooling and Structure
Both induction motors feature subtle yet impactful changes. Tesla added grooves to the motor housings, likely to reduce noise and improve cooling. Early observations suggest possible oil-cooling channels through the stator and rotor structures, though full confirmation awaits complete disassembly.
This attention to cooling is critical. Induction motors, especially in performance applications, generate substantial heat. Efficient thermal management extends motor life, preserves performance, and prevents costly failures.
Induction Motor Manufacturing Breakthroughs
One of the most groundbreaking revelations involved the manufacturing of the rear induction motor shafts. Tesla uses cold heading to near-net shape — a metal-forming process requiring minimal machining. This saves time, reduces waste, and improves material strength, contributing to lower overall motor cost and higher durability.
Additionally, Tesla chose not to skew the rotor bars inside the induction motor, a deviation from traditional practices that could simplify production without significantly impacting performance, thanks to careful electromagnetic design.
On-Road and Off-Road Flexibility
The Cyberbeast’s architecture offers both on-road efficiency and off-road capability. On the highway, Tesla’s system can shut off the rear induction motors, allowing the front PM motor to propel the truck alone with minimal energy loss. This design enhances electric range during typical driving.
For off-road use, Tesla integrated an electromagnetic locking differential on the front axle. This setup magnetically locks the front wheels together when engaged, delivering maximum traction without needing additional mechanical linkages or clutches. Simple, durable, and highly effective.
Final Impressions: Engineering Excellence With Room to Grow
The Tesla Cyberbeast motor teardown highlights a company continuing to push the envelope in EV design. Innovations like hairpin stator winding, clever bearing retention, and cold-headed shafts show Tesla’s relentless drive toward efficiency and cost reduction.
Still, opportunities for refinement exist. Moving back to segmented magnets could yield significant efficiency gains, especially critical as EV range remains a decisive factor for consumers.
Munro & Associates praises Tesla’s approach of prioritizing total lifetime cost. By optimizing durability and efficiency at the motor level, Tesla reduces total ownership costs for Cybertruck buyers — a key advantage as competition intensifies in the electric pickup market.
Tesla Cyberbeast Analysis Takeaways
- Shared motor tooling reduces manufacturing complexity and cost.
- Hairpin windings offer greater efficiency, particularly in high-voltage systems.
- Cold-headed shafts represent a major advance in affordable, durable EV motor manufacturing.
- Locking differentials improve off-road traction without adding weight or complexity.
- Segmentation of magnets could further boost electric range and thermal stability.
Tesla’s Cyberbeast motors reflect a mature, strategic application of lean engineering principles, with a few areas still ripe for future optimization.
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