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When it comes to pushing boundaries in EV engineering, few vehicles excite like the Tesla Model S Plaid. Munro & Associates recently conducted a detailed teardown of the Plaid’s dual motor assembly, offering a treasure trove of insights into Tesla’s forward-thinking design, cost-saving reuse strategy, and standout performance elements. This breakdown is a must-read for EV engineers, investors, and enthusiasts looking to understand what makes Tesla’s top-tier powertrain so formidable.
Forward-Compatible Inverter Design
Tesla’s approach to component reuse is on full display in the inverter design. The same inverter board is shared across the Model 3, Model Y, and S Plaid, with only minimal chip modifications needed. This standardization reflects excellent lean manufacturing principles: fewer SKUs, reduced complexity, and easier upgrades over time. Despite slight positional differences in components like capacitors, the boards remain near-identical—optimized for mass production and longevity.
Compact Dual Motor Housing
At the heart of the rear assembly are two motors and inverters, housed within a shared gearbox casing. Tesla engineers combined the stator and gearbox housing into a single cast piece, enhancing structural rigidity while minimizing the space footprint. Each motor features its own oil pump and heat exchanger, while an additional pump services the shared housing. This thermal management strategy reflects Tesla’s obsession with efficiency and simplicity.
The use of multiple dedicated oil pumps allows for more effective cooling during high-output operation. With the stators actively cooled through channels in the laminations and a continuous oil loop that includes the gearbox and inverter, this setup significantly reduces the risk of thermal fatigue—key in a vehicle that can sustain prolonged high loads. This attention to thermal dynamics helps preserve long-term reliability and peak performance.
Torque Vectoring Without a Differential
In a move that ditches mechanical complexity, Tesla uses independent motors on each rear wheel, eliminating the traditional differential. This configuration allows for precise torque vectoring, enhancing traction and cornering stability—especially beneficial in high-performance EVs. The Plaid’s ability to send instantaneous torque to each wheel individually means improved control during aggressive acceleration, sharp turns, and adverse road conditions.
Tesla’s software intelligently balances each motor’s output in real time, responding to traction loss or driver input with surgical accuracy. This “digital differential” not only saves weight and space but also provides more agility than traditional mechanical systems. In performance driving or emergency maneuvers, this system delivers quicker corrections and better stability.
Precision Bolting and Gasket Design
Tesla’s assembly quality shines through even in bolt placement. By aligning bolt directions, the team ensures optimal torque-to-yield tensioning, critical for aluminum casings. Even the gaskets impress: the Plaid uses laminated aluminum-and-rubber gaskets instead of RTV sealants. These premium gaskets endure high-pressure clamping without crushing—ideal for long-term reliability and serviceability.
Reused Yet Refined Stators
The stators in the Plaid are identical to those in the Model Y, highlighting Tesla’s consistent reuse of proven technology. They’re coil wound, three-phase stators, cooled through laminated channeling and insulated with paper slot liners. Once press-fitted into the housing through differential thermal expansion, the stator is locked in place with such precision that no fasteners are required.
A Rotor Wrapped in Carbon Fiber
Perhaps the most groundbreaking element is the rotor wrapped in carbon fiber. This prepreg wrap helps contain centrifugal forces at extreme RPMs. While this bobbin-style winding is unique, Sandy Munro suggests a knitted or woven carbon sleeve could offer superior structural strength. Still, the carbon wrap remains a notable first in EV motor design.
Beyond structural integrity, the rotor’s carbon wrap plays a critical role in dynamic balance and thermal control. Carbon fiber’s low thermal expansion helps maintain concentricity under extreme loads. Combined with the skewless laminate design, the result is smooth, pulse-free power delivery, a significant advancement for high-speed motors.
Innovative Laminate Stack and Magnet Configuration
The rotor’s laminate stack features a novel arrangement: bridges are removed between the magnets, maximizing the active area and enhancing flux density. Tesla claims a 25% boost in torque and power thanks to this redesign, a claim backed by internal patents.
Tesla’s choice to use long, unmagnetized rare-earth bars inserted post-lamination optimizes assembly efficiency while preventing magnetic interference during manufacturing. Final magnetization likely occurs after integration, maintaining precision placement. The extremely strong magnets tested during teardown further highlight Tesla’s use of high-grade materials, which are then validated through Gauss measurement in lab settings.
Explosive Inverter Failsafe: Safety First
Tesla has added a literal “bang” to safety with a plunger-based explosive charge built into the inverter bus bar. In an emergency, it physically severs power pathways—a hardware failsafe in addition to software and fuse-based systems. Although the demo lacked fireworks, the engineering is serious and speaks to Tesla’s commitment to redundant safety systems.
Magnet Force Testing: Model S Plaid Comes Out On Top
To quantify magnet strength, Munro’s team performed pull tests using a calibrated force gauge. Among the Tesla Model Y, Ford Mach-E, and BMW i3 motors, the Model S Plaid rotor magnets required the most force to detach—confirming Tesla’s use of extremely high-strength materials for performance advantages.
Key Takeaways from the Model S Plaid Motor Teardown
- Component Reuse: Tesla effectively shares inverters and stators across its fleet, minimizing cost while ensuring performance.
- Dual Motor Housing: Integrated designs reduce size, weight, and complexity.
- Rotor Innovation: Carbon wrapping and unbridged laminates show next-gen thinking.
- Thermal Management: Multi-pump cooling systems and premium gaskets enhance durability.
- Safety Engineering: Hardware-based power cutoffs show Tesla’s deep safety culture.
Explore More Munro Insights
If you’re as fascinated by EV technology as we are, check out more of Munro’s teardowns, expert reviews, and deep-dives. The Model S Plaid is just the tip of the iceberg. From inverter innovation to rotor re-engineering, there’s always more to uncover in the world of lean design and electric performance.