Electrical switching apparatus employing twice-energized trip actuator

An electrical switching apparatus for switching an electrical current flowing between a power source and a load, said electrical switching apparatus comprising:

• first terminal means for interconnection with said power source;
• second terminal means for interconnection with said load;
• separable contact means electrically interconnected between said first and second terminal means for movement between a closed position and an open position in order to switch said electrical current;
• operating means for moving said separable contact means between the closed position and the open position thereof, said operating means having a first position and a second position which corresponds to the open position of said separable contact means;
• sensing means for sensing said electrical current, said sensing means having an output with a sensed current signal corresponding to said electrical current;
• and
• trip means comprising:
• digital trip means having an input interconnected with the output of said sensing means, said digital trip means employing the sensed current signal to produce a trip signal at an output,
• shunt means having an output for continuously shunting only a portion of said electrical current, and
• trip actuator means for tripping said operating means to the second position thereof to move said separable contact means to the open position thereof, said trip actuator means including coil means having an input interconnected with the output of the digital trip means and also including at least one loop with an input interconnected with the output of the shunt means.

An electrical switching apparatus for switching an electrical current, said electrical switching apparatus comprising:

• separable contact means for movement between a closed position and an open position in order to switch said electrical current;
• operating means for moving said separable contact means between the closed position and the open position thereof, said operating means having a first position and a second position which corresponds to the open position of said separable contact means;
• sensing means for sensing said electrical current and outputting a sensed current signal corresponding to said electrical current;
• trip means employing the sensed current signal for producing a trip signal;
• means for continuously directing only at portion of said electrical current to effect trip actuation;
• and
• trip actuator means for tripping said operating means to the second position thereof to move said separable contact means to the open position thereof, said trip actuator means including an armature, coil means energized by the trip signal for driving the armature, and means employing said portion of said electrical current for coupling a magnetic field to the armature.

An electrical switching apparatus for switching an electrical current, said electrical switching apparatus comprising:

• separable contact means for movement between a closed position and an open position in order to switch said electrical current;
• operating moans for moving said separable contact means between the closed position and the open position thereof, said operating means having a first position and a second position which corresponds to the open position of said separable contact means;
• sensing means for sensing said electrical current and outputting a sensed current signal corresponding to said electrical current;
• trip means employing the sensed current signal for producing a trip signal;
• shunt means for shunting a portion of said electrical current;
• and
• trip actuator means for tripping said operating means to the second position thereof to move said separable contact means to the open position thereof, said trip actuator means including coil means for energization by the trip signal and also including at least one loop energized by the portion of said electrical current,
• wherein said electrical current has a first magnitude at a point of actuating said trip actuator means by said at least one loop energized by the portion of said electrical current,
• wherein said electrical current has a second magnitude at a point of blow-open of said separable contact means, and
• wherein the first magnitude is about equal to the second magnitude.

An electrical switching apparatus for switching an electrical current flowing between a power source and a load, said electrical switching apparatus comprising:

• first teal means for interconnection with said power source;
• second terminal means for interconnection with said load;
• separable contact means electrically interconnected between said first and second terminal means for movement between a closed position and an open position in order to switch said electrical current;
• operating means for moving said separable contact means between the closed position and the open position thereof, said operating means having a first position and a second position which corresponds to the open position of said separable contact means;
• sensing means for sensing said electrical current, said sensing means having an output with a sensed current signal corresponding to said electrical current;
• and
• trip means comprising:
• digital trip means having an input interconnected with the output of said sensing means, said digital trip means employing the sensed current signal to produce a trip signal at an output,
• shunt means having an output for shunting a portion of said electrical current, and
• trip actuator means for tripping said operating means to the second position thereof to move said separable contact means to the open position thereof, said trip actuator means including coil means having an input interconnected with the output of the digital trip means and also including at least one loop with an input interconnected with the output of the shunt means,
• wherein said electrical current has a first magnitude at a point of actuating said trip actuator means by said at least one loop energized by the portion of said electrical current,
• wherein said electrical current has a second magnitude at a point of blow-open of said separable contact means, and
• wherein the first magnitude is about equal to the second magnitude.