INTRODUCTION

BE3 ac voltage relays provide voltage monitoring and protection in

both single-phase and three-phase systems. They are used in

applications such as utility mains failure, regulation of power

supplies, and to protect voltage sensitive equipment. Undervoltage,

overvoltage, and combined over/undervoltage units are available.

BE3 ac voltage relays operate when the adjustable trip point is

reached. An external time delay control is provided with an

adjustment of 0 to 10 seconds (relay operating time is typically 200

milliseconds). This time delay may be used to prevent false tripping

when there are slight variations in the voltage supply. 

On overvoltage units, the output relay energizes when the input

signal exceeds the trip point. On undervoltage units, the output

relay de energizes when the input signal goes below the trip point.

A red LED indicates the state of the relay. A green LED indicates

the condition of the power supply.