Circuit Breaker Trip 1 & Trip 2 for a DC Load Calculation
Circuit Breaker Trip 1 & Trip 2 for a DC Load Calculation
(OP)
Greetings forum goers.
I have a question for you. For the purposes of battery sizing (specifically amp hour rating), I have generally used a calculation that accounts for only one trip coil per circuit breaker drawing current during the small portion of the 8 hour DC curve where circuit breakers are tripping.
My question is, should I also be accounting for the trip 2 coil when the breaker has one? I guess the real question is, does the trip 2 coil see a current when the trip 1 coil operates?
Thanks!
I have a question for you. For the purposes of battery sizing (specifically amp hour rating), I have generally used a calculation that accounts for only one trip coil per circuit breaker drawing current during the small portion of the 8 hour DC curve where circuit breakers are tripping.
My question is, should I also be accounting for the trip 2 coil when the breaker has one? I guess the real question is, does the trip 2 coil see a current when the trip 1 coil operates?
Thanks!






RE: Circuit Breaker Trip 1 & Trip 2 for a DC Load Calculation
RE: Circuit Breaker Trip 1 & Trip 2 for a DC Load Calculation
What I'm wondering is, based on the mechanical nature of the trip mechanism, do they both draw the full rated trip current? Honestly, the battery capacity isn't much of a concern as this is only a few cycles of an 8 hour period. It's more that I'm curious.
RE: Circuit Breaker Trip 1 & Trip 2 for a DC Load Calculation
RE: Circuit Breaker Trip 1 & Trip 2 for a DC Load Calculation
Where's zogzog these days? He overhauls circuit breakers for a living and might have a different perspective.
RE: Circuit Breaker Trip 1 & Trip 2 for a DC Load Calculation
RE: Circuit Breaker Trip 1 & Trip 2 for a DC Load Calculation
And being dual redundant, the protection schemes are duplicates, meaning when a fault occurs they race to trip the protected zone out of service, hence by design they should both operate together.
Since during such equipment outages both trip coils will be energized from the same source, and also since a system disturbance could occur while the outage is in effect, would it not be better to plan for such a contingency right out of the gate?