The paper proposed a design scheme of time-delay protection circuit for voltage-loss on the basis of analysis of large-scale power failure phenomenon of power supply and distribution system of underground coal mine due to transient voltage-loss. and introduced design idea and working principle of the circuit in details. The circuit uses double rectifier to charge capacitance and contr... https://allfixelectricales.shop/product-category/door-gasket-drain-hose/