Cor van de Water via EV wrote:
I believe that Lee responded to a similar question a while back that
there are some breakers, where a circuit is connected to the load
side of the breaker so if it trips then it is no longer powered but
put it in reverse and it remains powered and might overload. I forget
what type of circuit was on the load side of those breakers, it might
be a coil.
Yes; a GFCI breaker is a common example. The GFCI circuitry is powered
from the load side of the breaker, so it is automatically switched off
when the breaker trips.
Some breakers have "trip" coils that get energized to force it to
rapidly trip when some threshold current, rate-of-rise in current, arc
detection, or other event occurs. These circuits are likewise powered
from the load side, so they get turned off automatically when the
breaker trips.
The other reason that polarity can matter on a DC breaker is that there
can be arc-suppression components that depend on knowing the polarity.
For instance, blow-out magnets that push the arc in a "safe" direction
when the current flows from line to load. If the current flow is
backwards, the arc gets pushed the "wrong" way, where it can damage
other parts inside the breaker.
As an example, I have a Heinemann 160vdc breaker. It has a screened arc
port, and you can clearly see the blowout magnets on each side of the
contact. When it opens a current from line to load, the magnets blow the
arc OUT the screened port. If it opened with a current from load to
line, the arc would be blown INTO the guts of the breaker, where they
could do a lot of damage.
You really have to contact the manufacturer of the breaker and ask THEM
for a definitive answer on the particular make/model you are using.
--
A designer knows he has achieved perfection not when there is
nothing left to add, but when there is nothing left to take away.
-- Antoine de Saint Exupery
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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