Two common techniques to protect pump from "dry-run"
By sensing water (liquid) flow through output pipeline
By sensing current of pump supply
1. By sensing water (liquid) flow through output pipeline
By using sensors like floating magnet sensor, ultrasonic sensors, contact type liquid sensor, we can sense water flow through pipeline. And when there is not water, its give signal to starter switch to shut down pump supply.
2. By sensing current of pump supply
In this method we continuously read the current of pump. And when pump current reading goes below pre-set current level, it is assumed that pump is running freely i.e. dry-run. In such case, current sensor gives signal to shut down pump.
