Mechanical Design Engineer - Electromechanical

Mainspring Energy

Menlo Park, USonsite$114k-$140k/yrPosted Jul 25, 2026
Posting intelligenceActively listedReposted 7×, possible evergreen/ghost posting

Skills

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About the role

About Mainspring

Mainspring Energy manufactures and delivers fuel-flexible, low-emissions local power solutions that rapidly add new capacity and deliver reliable, affordable, and sustainable electric power. The company began commercial shipments of its Mainspring Linear Generators in 2020 and today has hundreds of megawatts in advanced development and field operations for leading Fortune 500 companies, data centers, and utilities. Mainspring also partners with global energy leaders including AEP, NextEra Energy Resources, Schneider Electric, and more.

The core values that ground our work, guide our decisions, and connect us together:

Pragmatic Optimism

Excellence without Ego

Proactive Collaboration

Job Overview

Mainspring is seeking Mechanical Design Engineers with a focus on designing electrical enclosures and cables while improving functionality and system-level performance. In this role, you will lead projects from setting requirements, designing, conducting cross functional reviews, coordinating testing and release to ensure that key electrical subsystems meet challenging technical requirements with a potential for direct reports. Ideal candidates will have a strong combination of technical expertise and the drive to solve complex problems in a collaborative environment.

Core Responsibilities

Involved in brainstorming and technical review sessions to develop innovative solutions that enhance the performance and cost-efficiency of the Linear Generator and electrical subsystems

Ownership of design, optimization, and execution of electrical hardware, balancing cost reduction, safety improvements, and system-level reliability

Collaborate with reliability and test teams to validate systems and components, ensuring fast iteration cycles and incorporating feedback to drive the next-generation deployment of the Linear Generator

Collaborate cross-functionally with electrical engineering, manufacturing engineering, NPI, and external suppliers to deploy new designs into production, ensuring all systems meet the necessary performance and manufacturability requirements

Development of electrical hardware, including requirements development, prototyping, testing, iteration, and tooling, ensuring project milestones are met and resources are allocated effectively

Qualifications

Degree: BS or MS in Mechanical Engineering or a similar engineering field from an accredited institution. Experience and degree will determine the level, with the following minimum requirements: Senior: BS + 3 years or MS + 2 years

Experience designing electrical enclosure and/or cable design

Expertise in sheet metal design for medium-volume production, electrical component specification, mechanical design for electrical systems, and design-for-manufacturability challenges

A solid understanding of electrical engineering principles and thermal modeling, and the ability to integrate them effectively into larger system designs

Experience in SolidWorks and PDM (or a similar CAD version control system). Experience with CFD, FEA, and programs like SolidWorks Flow Simulation or Ansys is a plus

Passion for creating innovative and cost-effective solutions to enable the large-scale deployment of zero-carbon energy technologies

This position is onsite at our Menlo Park HQ. The salary will be adjusted to reflect local market conditions based on employee location as well as the experience of the employee. Along with the base salary, Mainspring offers pre-IPO stock options + benefits.

Does your experience not meet all of our posted requirements? Studies have shown that some people are less likely to apply to positions unless they meet every listed requirement. At Mainspring, we are committed to building a diverse, inclusive, flexible, and collaborative environment, so if you want to help us transition the world to clean and affordable electricity, and don’t meet all posted requirements for a particular role, we’d still love to hear from you. Mainspring can sometimes be flexible enough to shift responsibilities for the right person, or otherwise identify open or upcoming roles that may better fit your professional background.

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. We generally do not negotiate on salary once we have made an offer. The level of pay within the range will depend on a variety of job-related factors that may include location, relevant prior experience and/or education, or particular skills and expertise. New hires joining the company tend to be paid within the starting base pay range noted above, with opportunities to increase pay over time based on development of additional skills, competencies, and company-specific knowledge.

We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses and identifying potential inconsistencies or verification signals in application materials based on available information. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.

Compensation

This Design Engineer role pays $114k-$140k/yr. Within typical range for design engineer roles in United States.

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