Our client wished to provide a means of protecting localised mains electricity circuits from momentary high loads as well as protecting the load from mains surges in industrial applications.
We specified and developed a DIN rail mounting device which, after a random delay, switches the appliance at the mains zero-cross. This ensures that on a particular circuit the various appliances do not switch on together. In addition it disconnects the appliance if it draws too much current or if the peak mains voltage exceeds 400Vdc. The speed of response to rapid changes as well as the robustness of the switch were major challenges. The resulting product employs embedded code and high speed hardware to interpret current and voltage signals and to control the switch.
The circuit protector is useful in protecting local mains networks from inadvertent shut-down due to momentary glitches as well as protecting the load.