Thermal sensor clamp for Clarke 150A MIG welder

thingiverse

These two brackets are designed for mounting standard NC thermal safety switches directly onto a Clarke 150A transformer-type MIG welder's transformer and inductor. To ensure optimal performance, they must be printed using a temperature-resistant polymer such as colorfabb's HT filament. I opted for 65C thermal switches, which might be slightly over-sensitive; if I were to do it again, I would likely choose 75C units for better accuracy. Using silicone thermal contact pads is also highly recommended, as they provide a secure connection between the switches and windings without compromising performance. For electrical integration, I connected both switches in series with the main contactor's coil. While there might be a more refined solution available, this approach was the most feasible given the [rLab] MIG welder's extensive modifications. Additionally, I added a 240V neon light to the front panel, wired across the switches, which illuminates when the welder attempts to operate but is inhibited by the thermal safety feature, providing an unmistakable warning signal.