INTRODUCTION

BE3-25 sync-check relays are used to ensure that two ac

circuits are synchronized. In order to be synchronized, the

frequency, phase angle, and voltage of the two circuits must

be within preset limits. When this occurs, the BE3-25 output

relay energizes. The primary application of the BE3-25 is to

enable additional generators to be brought on-line without

machine damage or system disturbance. The BE3-25 can

also be used to supervise reclosing or in any instance where

the danger of paralleling two circuits out of synchronism

exists.