Incredibly good Meanwell surge protection unit (with schematic)

With Meanwell being one of the biggest players in the professional power supply industry, I had high expectations of this surge protection unit designed for use with LED drivers in outdoor signage, but also very suitable for many applications where you want to protect expensive electronic circuitry against rogue voltage transients caused by lightning strikes or electrical supply incidents.

The quality of this unit was an absolute treat. Robustly made with no PCB tracks or solder joints to fail. Instead the unit is composed of a housing for three separate thermally protected MOV modules, and the stout wires have been bent and soldered directly to the heavy duty incoming wires.

The unit has been soldered in situ and then filled with coarse white quartz-like sand and then a layer of resin added to reduce the risk of water ingress.

Fault indication is in the form of two traditional gallium phosphide green LEDs that will indicate when a thermal fuse has tripped. The thermal fuses are triggered when the MOVs (Metal Oxide Varistors) reach the end of their useful life and start passing enough current to get hot.

These modules are so rugged and affordable that they would be a good addition to protect HVAC, computer and industrial control systems. In some instances it could be useful as a whole-home protective device.


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