Abstract:

Balance force relays have extensive applications,yet manufacturers frequently encounter phenomena such as ‘two-step engagement’ and ‘two-step release’ during product commissioning.Such occurrences may reduce the electrical lifespan of the relays.The mechanisms underlying ‘two-step engagement’ and ‘two-step release’ are investigated,and their impact on product longevity is analyzed.The operating principle of balance force relays and the ideal matching relationship between attraction and repulsion forces are first elucidated from a magnetic circuit perspective.It then analyses the mechanisms behind ‘two-step engagement’ and ‘two-step release’ occurring during specific phases,along with their impact on product lifespan.Finally,selected samples undergo lifespan testing,confirming that ‘two-step engagement’ during static overtravel and ‘two-step release’ during dynamic overtravel reduce product lifespan,consistent with analytical findings.

Key words: balance force relay, two-step engagement, two-step release, electrical life