Automatic A-C. network switching units

The desirable characteristics of automatic switching units designed for application in secondary a-c. distribution networks are discussed in this paper. Descriptions are given of units designed for wall mounting and for manhole installation. These units are connected to the low-voltage side of the network transformer for the purpose of automatically disconnecting a transformer from the low-voltage network whenever a fault develops on a primary feeder connected to the transformer. When proper voltage is restored to the primary feeder the unit should automatically reclose.