The basics of device circuit breakers | Glossary
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Glossary
Active current limiting Limiting of current flowing in any operating state to a specific manufacturer-specified maximum value . This applies both for fault currents as well as for starting currents .
Ambient temperature Temperature of the air surrounding the equipment .
Auxiliary contact Contact in the auxiliary circuit that is used as a remote indication contact .
Backup fuse Integrated , additional fuse element that protects the device circuit breaker in the unlikely event that the electronics fail .
Changeover contact Signal contact with three connections that provides N / C contact and N / O contact functions .
Clearance This is the shortest distance between two conductive parts .
Conditional short-circuit current rating Conditional short-circuit current rating I nc describes the maximum current that a circuit breaker or protective device can interrupt , where the operation of the circuit breaker need not be preserved for further use . The conditional short-circuit current rating must be larger than the maximum possible short-circuit current in the circuit . This is understood as the prospective short-circuit current that would be flowing in the circuit over the shortest path without any protective device .
Connection method Specification for conductor connection technology , e . g ., a screw terminal block or screw-less push-in connection .
Creepage distance Shortest distance along the surface of an insulation material between two conductive parts .
Current limiting See Active current limiting
Device circuit breakers Circuit breakers that protect from possible failures resulting from short circuit or overload . They are specially designed to protect devices and actuators in technical systems and machines .
Electrical isolation Additional physical interruption of the primary load current across an actual clearance by self-opening contacts .
Electronic interlock Locking mechanism to prevent an accidental adjustment to the nominal current of each channel once it is set .
Fuses Fuses open a circuit and shut off the current if a permitted current value is exceeded over a long period of time .
Main contact Contact in the main circuit that conducts the current when closed .
Miniature circuit breakers These are used to protect cables from damage that could occur as a consequence of overload or short circuit .
MOSFET Metal oxide semiconductor field-effect transistor in an electronic circuit breaker .
MTBF ( Mean Time Between Failures ) The expected operational period between two consecutive failures .
Number of channels There are single-channel and multi-channel device circuit breakers . In multi-channel circuit breakers , the individual channels are independent of each other and protect different paths .
Number of positions The number of positions indicates how many current paths are being protected simultaneously and shut down by multiple positions in the event of a fault . The individual current paths are coupled together and must be shut down together in the event of a fault .
N / C contact Floating auxiliary contact . Opens if the main contact is closed .
N / O contact Floating auxiliary contact . Closes if the main contact is closed .
Operating characteristic curves Characteristic curves that describe the behavior of a device circuit breaker below specific current and voltage values .
Overcurrent shutdown Conventional circuit breakers shut off the overcurrent in the event of a fault within the tripping range of their time-current characteristic curve .
Overload current Overload current is current in excess of the nominal current and must not be allowed to continue to flow .
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