INTRODUCTION

BE3-47N phase balance relays protect three-phase lines,

transformers, motors, and generators against phase

unbalance, phase loss, and phase reversal. BE3-47N/27

relays have the added feature of undervoltage protection.

The output relay energizes and the red RELAY LED lights

when a balanced input with the proper phase sequence is

sensed. The output relay de-energizes and the RELAY LED

goes out when a fault condition is detected. The green

POWER LED indicates the condition of the power supply.

Two external controls are provided: UNBAL (unbalance) and

DELAY. The UNBAL control adjusts the percentage of

unbalanced voltage at which the relay trips. The DELAY

control provides an adjustable time delay to prevent tripping

on voltage transients.