Building power overcurrent protection with restoring on timer
2011 (2 weeks), private project, 1 developer
result: 1 sample is implemented
tools: Oscilloscope & solder iron
It is developed for protection of country side building that is 7-15 kW load of non-stable 220V power network. It disconnects load (building with power stabilizer) if its current exceeds the customizable level (25-70 amperes) and then it runs timer. Timer delay may be set in the range of 2 to 24 minutes. Device restores power to load when timer’s delay is passed.
It is designed to work at wide range of power: 90 to 330 volts (tested). In normal condition (220V) this device consumes only 2,5 Watts and 6 Watts when load is disconnected.
Such device becomes useful when power stabilizer does not have automatic restoring of power after overcurrent condition. This leads to total discharging of backup batteries of UPS which follows stabilizer even if power is already restored.
At the country side overcurrent condition often occurs when power network voltage drops. For example, if voltage drops to about 147 volts then input current of stabilizer rises in 1.5 times (while building consumes the same power after stabilizer).