MaySpare 12V Trombetta-Style 3-Terminal Solenoid Relay — 200A Transient, Sealed Steel Case

The MaySpare Max Transient 200A Trombetta 12V solenoid is a heavy-duty, 3-terminal SPST relay designed to control starter, winch, and marine circuits with robust copper coil construction and a sealed steel housing.

This compact 12-volt solenoid by MaySpare combines durable materials and high transient capacity to handle demanding cranking and accessory loads. Built with a plated steel case, a 3-pole configuration, and 10-32 terminals, it suits applications where reliable switching, corrosion resistance, and short-duration high-current performance matter. The solenoid is intended primarily for starter engagement and intermittent heavy-duty tasks rather than continuous long-term loads.

How does this solenoid perform under heavy loads?

The unit is rated for transient currents up to 200 amps and a continuous rated current of around 100 amps, making it suitable for short bursts of high demand such as winch pulls or starter engagement. It uses a copper coil engineered to withstand higher temperatures and a sealed housing to limit corrosion in harsh environments.

• Transient capacity rated to 200A for brief high-current events
• Continuous duty recommendation: up to 100A with cooling breaks
• Copper coil rated to 180°C for thermal resilience
• Sealed, plated steel case for environmental protection

What mounting and terminal options does it offer?

The solenoid has a flat-base metal case with a 180° flat mounting bracket and two mounting holes sized 5/16 x 19/32 positioned 2-13/64 inches apart, making it compatible with many vehicle and marine mounting arrangements. Electrical connections use common 10-32 stud terminals for easy wiring to batteries, starters, or winches.

• Flat-base metal case with 180° mounting bracket
• Mounting hole spacing: 2-13/64 inches on centers
• Mount hole size: 5/16 x 19/32 for secure bolting
• 10-32 threaded terminals for standard electrical fittings

Is this solenoid suitable for marine and outdoor use?

Yes — the solenoid’s exterior receives an environmental plating and the unit is sealed to reduce moisture and salt intrusion. That said, it is optimized for starter and intermittent tasks; continuous submersion or constant high-current duty without rest is not recommended.

• Plated steel case to resist rust and salt spray
• Sealed construction helps prevent corrosion of internal parts
• Best for intermittent marine and vehicle applications, not continuous duty
• If prolonged operation is needed, contact the supplier for alternatives

How long can I run it before it needs to cool down?

The solenoid is designed for starter-style operation where short activations are normal. For continuous-duty scenarios, the manufacturer recommends limiting sustained operation to around five minutes under 150 amps, then allowing a cool-down period to avoid overheating.

• Recommended maximum continuous runtime: ~5 minutes under 150A
• Longer or repeated runs require cooling intervals to prevent damage
• Not intended for nonstop high-current applications without breaks
• Contact MaySpare if you need a solenoid rated for extended duty

Who is this for: This MaySpare Trombetta-style 12V 3-terminal solenoid is aimed at mechanics, boat owners, off-road enthusiasts, and fleet operators who need a rugged starter or winch relay that tolerates occasional heavy current and corrosive conditions. Choose it when you need a compact, sealed, and copper-coil solenoid for intermittent high-load switching; seek a continuous-duty model if your application requires sustained long-duration current.