초록 ▼

An isolation circuit, which draws essentially zero current in a normal or stand-by state, uses a normally closed relay in combination with a storage element. A capacitor can be used as the storage element to energize the relay, using previously stored energy, in the event that a communication line t

An isolation circuit, which draws essentially zero current in a normal or stand-by state, uses a normally closed relay in combination with a storage element. A capacitor can be used as the storage element to energize the relay, using previously stored energy, in the event that a communication line to which the isolator is coupled exhibits a short circuit or low voltage condition. In this instance, the prestored energy on the capacitor activates the relay for a predetermined period of time, thereby open circuiting the communication line. When voltage is reapplied to one side of the isolator circuit, the relay is continuously energized and maintained in its open circuit condition until the low voltage or short circuit has been remedied.

대표청구항 ▼

An isolation circuit for responding to and isolating a short circuit or a high loading condition in an electrical transmission system in which a voltage difference above a predetermined value is periodically or usually maintained across at least two conductors comprising: a normally-closed, non-latc

An isolation circuit for responding to and isolating a short circuit or a high loading condition in an electrical transmission system in which a voltage difference above a predetermined value is periodically or usually maintained across at least two conductors comprising: a normally-closed, non-latching, relay having an energy input as well as first and second switch ports, said switch ports of said relay being couplable in series with one of the conductors; the said relay maintaining a very low impedance when the line voltage temporarily goes to a low value until it switches to an open state; an energy storage element coupled to said energy input of said relay, said energy storage element being capable of storing a predetermined quantity of energy in the presence of the voltage difference; and switching circuitry coupled to said switch ports, to said energy input of said relay and to said energy storage element, and being couplable to at least one of the conductors, said circuitry being capable of changing state in the presence of the short circuit or high loading condition where the line voltage will not go above a predetermined level, thereby discharging said stored energy of said energy storage element into said energy input and opening said relay, thereby isolating the short circuit or high loaded section.