Senior Staff Mechanical Engineer - Electromechanical

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 looking for a Senior Staff Mechanical Engineer — Electromechanical to lead the design and integration of electrical enclosures, busbars, and cable systems for our next-generation energy platforms.

This is a highly visible technical leadership role focused on solving difficult real-world engineering problems across power electronics packaging, harsh-environment durability, manufacturability, and system integration. You’ll help shape core product architecture while working on systems deployed across demanding operating environments ranging from coastal and desert conditions to future megawatt-scale applications.

We’re looking for an engineer who understands how electrical and mechanical systems behave in the real world — and can drive robust electromechanical solutions from concept through production.

• Lead the design and development of electrical enclosures, busbars, cable assemblies, and integrated electromechanical systems
• Drive packaging decisions balancing thermal performance, vibration durability, EMI considerations, creepage/clearance, manufacturability, serviceability, and cost
• Own hardware through the full product lifecycle including concept development, prototyping, validation, production launch, and sustaining engineering
• Partner closely with Electrical, Reliability, Manufacturing, Test, NPI, and supplier teams to develop robust hardware solutions
• Solve challenging environmental durability problems involving corrosion, outdoor deployment, thermal extremes, and vibration-heavy operating conditions
• Lead root-cause investigations for field and test failures and drive corrective actions into production
• Mentor engineers through design reviews and technical leadership on complex problems

• Busbar design experience
• HV power systems experience
• Cable harness and routing design experience
• Experience with corrosive or outdoor deployment environments
• Familiarity with FEA tools such as Ansys
• Background in EVs, power electronics, energy systems, industrial equipment, or ruggedized hardware systems

• BS or MS in Mechanical Engineering or related field
• 12+ years of experience designing electromechanical hardware systems
• Proven experience designing electrical or electronic enclosures through production release
• Strong background in sheet metal design and mechanical-electrical integration
• Experience packaging electrical components such as fuses, contactors, relays, PCBAs, busbars, cables, connectors.
• Experience in designing systems such as inverters, controllers, fuse systems, batteries, or other power electronics.
• Understanding of thermal management, vibration, environmental durability, grounding, creepage/clearance, and EMI-related packaging constraints
• Experience supporting validation, testing, manufacturing launch, and sustaining engineering
• Proficiency with SolidWorks and PLM systems