CobyRupert
Super Member
Not sure if there's a typical usage for shunt trip breakers.
They're typically used when a full relay or contactor isn't required, usually when you just want a way to (automatically) turn off a circuit, but don't need it to automatically turn on.
Load shed is one usage, another might be if a (fire) alarm is triggered and you want to cut the power to something.
Because they are "one way" and manually resetting is required, they're usually reserved for cutting power in "abnormal" situations; were it's not too inconvenient if the power doesn't automatically coming back on once other conditions are satisfied.
Again, look into wiring circuit through the "normally closed" (N.C.) contacts of a regular relay, where the coil only gets energized, opening the contacts from the momentary load shed signal.
You will then need wiring, and a normally open (N.O.) contact on the same relay to "latch" the coil. (This uses a normally open (N.O.) contact of the relay (that closes when relay is energized) so that relay stays energized when the initial momentary load shed contact opens. Basically the relay's normally open (N.O.) contact is wired in parallel with the load shed signal's contact to the coil.) You then need a manual "Reset" pushbutton (normally closed) wired in series with this N.O. contact, ahead of the coil, that opens to "unlatch" (de-energize) the coil (and all contacts go back to their normal (coil is de-energized) status.
^Hard to describe in words, put REALLY simple if diagramed. I'll try to find an example.
They're typically used when a full relay or contactor isn't required, usually when you just want a way to (automatically) turn off a circuit, but don't need it to automatically turn on.
Load shed is one usage, another might be if a (fire) alarm is triggered and you want to cut the power to something.
Because they are "one way" and manually resetting is required, they're usually reserved for cutting power in "abnormal" situations; were it's not too inconvenient if the power doesn't automatically coming back on once other conditions are satisfied.
Again, look into wiring circuit through the "normally closed" (N.C.) contacts of a regular relay, where the coil only gets energized, opening the contacts from the momentary load shed signal.
You will then need wiring, and a normally open (N.O.) contact on the same relay to "latch" the coil. (This uses a normally open (N.O.) contact of the relay (that closes when relay is energized) so that relay stays energized when the initial momentary load shed contact opens. Basically the relay's normally open (N.O.) contact is wired in parallel with the load shed signal's contact to the coil.) You then need a manual "Reset" pushbutton (normally closed) wired in series with this N.O. contact, ahead of the coil, that opens to "unlatch" (de-energize) the coil (and all contacts go back to their normal (coil is de-energized) status.
^Hard to describe in words, put REALLY simple if diagramed. I'll try to find an example.
