Senior Mechanical Engineer - Electromechanical

Senior Staff Mechanical Engineer - Electromechanical

Mainspring Energy is revolutionizing power generation with the world’s most flexible and adaptable local power generation technology, the Mainspring Linear Generator. Commercial, industrial, and utility leaders are choosing Mainspring over traditional options such as engines, turbines, and fuel cells to quickly and reliably deliver local power for EV charging, commercial facilities, data centers, and grid‑scale operations. The Linear Generator is fuel flexible, ramps up and down to meet demand, and uses a flameless reaction with near‑zero NOx emissions.

Backed by top‑tier investors including Khosla Ventures, Bill Gates, American Electric Power, Lightrock, and General Catalyst, Mainspring designs, manufactures, and delivers its products across the U.S. and is scaling for international expansion. Our vision is an affordable, reliable, net‑zero carbon grid, and we are hiring diverse talent to meet growing global demand.

Mainspring is seeking a Senior Staff Mechanical Engineer focused on designing electrical enclosures and cables while improving functionality and system‑level performance. This role owns engineering development projects, guides technical decisions, and influences design across teams. You will work with cross‑functional stakeholders to ensure that key electrical and mechanical subsystems meet challenging requirements from concept through manufacturing launch. Direct leadership of engineers, mentoring, and coordination across disciplines are critical.

Ideal candidates combine technical expertise, leadership skills, and a drive to solve complex problems collaboratively.

• Lead ideation and design reviews to develop innovative solutions that enhance performance and reduce cost of the Linear Generator and its electrical subsystems.
• Own the structure, layout, optimization, prototyping, testing, and deployment of electrical enclosures and harnesses.
• Partner with Electrical, Reliability, Test, NPI, Manufacturing, and supplier teams to define design direction, validate solutions, and meet project milestones.
• Oversee execution by setting requirements and coordinating across disciplines to maintain cohesive technical direction.
• Manage and mentor engineers, guiding technical decisions, setting priorities, and supporting professional growth.
• Proactively balance timelines, resources, and risks to ensure consistent delivery on key engineering initiatives.

• BS or MS in Mechanical, Electrical, or related engineering field with at least 11 years of industry experience.
• Proven ownership of electrical enclosure and cable designs, with experience influencing cross‑functional teams.
• Deep expertise in sheet metal, mechanical‑electrical integration, and design for manufacturability.
• Strong foundation in electrical principles, thermal modeling, and system‑level design.
• Proficient in Solid Works and PDM; experience with CFD/FEA tools (e.g., Ansys) is a plus.
• Demonstrated ability to make technical trade‑offs, guide design direction, and deliver complex systems.
• Passion for mentoring engineers and advancing high‑impact, low‑carbon energy technologies.

We encourage applicants who do not meet every listed requirement to apply; we may adjust responsibilities or explore other roles that better fit your background.

In more traditional words, Mainspring Energy, Inc. is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, protected veteran status, or disability.

This compensation and benefits information is based on Mainspring Energy’s estimate as of the date of publication and may be modified in the future. Pay within the base range will depend on location, experience, and skills. New hires generally start within the noted base salary range, with opportunities for increases over time.

We may use artificial intelligence tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are made by humans. For more information on how data is processed, please contact us.

This position is onsite at our Menlo Park HQ. The salary will be adjusted to reflect local market conditions based on employee location and experience. In addition to base salary, Mainspring offers pre‑IPO stock options and benefits.

Mid‑Senior level

Full‑time

Engineering and Information Technology

Electric Power Generation

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