Overcurrent Protection Symbol

The symbol for consist of two parallel lines inside and sometimes extending out of a circle.

Overcurrent protection symbol. Overcurrent operation below a set value e g. The overcurrent relay is defined as the relay which operates only when the value of the current is greater than the relay setting time. Depending on the time of operation the overcurrent relay is categorized into following types. The overcurrent relay can be used as overload thermal protection when protects the resistive loads etc however for motor loads the overcurrent relay cannot serve as overload protection overload relays usually have a longer time setting than the.

The overcurrent protection is a bigger concept so that the overload protection can be considered as a subset of overcurrent protection. Instantaneous overcurrent relay single line symbols. Symbol can also be used for. Underimpedance operation above a high set stage examples of protection relays relays and relay parts auxiliary relay with mechanical contacts auxiliary relay block symbol static relay with terminals for external auxiliary voltage supply u relay with make contact delayed when the relay is.

Only action is descripted and a switch is shown for clarification. A fuse is an overcurrent protective device containing a calibrated current carrying member that melts and opens a circuit under specified overcurrent conditions. It protects the equipment of the power system from the fault current. In the design of electrical power systems the ansi standard device numbers ansi ieee standard c37 2 standard for electrical power system device function numbers acronyms and contact designations identifies the features of a protective device such as a relay or circuit breaker these types of devices protect electrical systems and components from damage when an unwanted event occurs such.

Directional overcurrent protection for distribution networks in which the neutral earthing system varies according to the operating mode based on measured residual current. Overcurrent protection nen j 74 groundfault protection nen j 76 under voltage protection 02 12 07 automatic return the triangle is pointed in the return direction 02 12 11 mechanical interlock between two devices 02 12 12 latching device note. Fuses are devices containing a small piece of special wire that melts when the intensity of the current flowing through it for a certain period of time exceeds a set value thus protecting the rest of the electrical circuit overloads. Schedules are typically provided to detail the circuits and overcurrent protection required for distribution equipment.