The scientific use of breaker some attention
Dc circuit breakerNot only can be used to distribution power, not frequently start asynchronous motor, the power supply line and motor, to carry out protection, in normal circumstances connect and disconnect circuit, and can be used for resection of short circuit fault current, that is to say it also bear the control and protection of dual task.，But in recent years,ircuit breakerAccidents happen together, common havercuit breakerFailure, heat, sound is too large, serious andircuit breakerSuddenly combustion and explosion accident.Small make up for everybody below it summarizes some explosion caused by the cause of the accident and the corresponding solutions, will see the forehead.
Dc circuit breakerInstall strict inspection before its performance index should comply with the technical requirements.Because if repair quality does not meet the requirements.Such as maintenance change points, switching speed, change breaker arc distance, which made the circuit breaker's breaking capacity to reduce.if ircuit breakerThe breaking capacity is too small;When the short-circuit,Circuit breakeran't cut off short circuit current, cause circuit breaker burst into flames.
Improper operation and maintenance.Dc circuit breakerMany cutting short circuit current, if not timely arrange maintenance but many strong sending, make the circuit breaker many times by the short circuit current impact.These all make circuit breaker block ability is reduced, and thus cause circuit breaker burst into flames.So to strengthen the operation and maintenance and management.Circuit breaker operation, should do patrol inspection work, make circuit breaker normal operation and fault tripping frequency statistics, in order to arrange maintenance time.
Insulating oil not pure.rcuit breaker的。The oil in a lot of free carbide, a large number of aging, oil in tide, water, lead to oil is pure, can make circuit breaker internal happen flashover and cause an explosion.This requires regular insulation test.Especially the thunderstorm season before the preventive test.
In addition peacetime still want to do more preventive maintenance, to ensure that the quality of maintenance.doDc circuit breakerMoistureproof, prevent leakage and pollution prevention work to prevent the circuit breaker water sweat.For these electrical device, such as contactor, choose high quality products is very important, but in the operation of the maintenance and prevent the crisis is more important.
Concludes attention points:Dc circuit breakerRated voltage is equal to or greater than line rated voltage;Circuit breaker undervoltage tripping device rated voltage is equal to rated voltage line;Circuit breaker shunt tripping device is equal to the rated voltage control of the power supply voltage;Dc circuit breakerShell frame levels of rated current is equal to or greater than line calculation load current;Circuit breaker rated current is equal to or greater than line calculation current;Circuit breaker of rated short circuit hige capacity greater than or equal to line the biggest short circuit current;The end of lines single phase short circuit current to earth is equal to or greater than 1.5 times the circuit breaker instantaneous (or short time delay) trip setting current;rcuit breakerType should comply with the installation conditions, protection performance and mode of operation requirements.
Suggestions are as follows:
(1) by the calculation of line current to determine rated current of the circuit breaker,
2) breaker short circuit setting current should avoid line the normal work of the starting current.
(3) the maximum short-circuit current in line to check low voltage circuit breaker's breaking capacity;
(4) according to the line of the minimum short circuit current to check circuit breaker action sensitivity, namely line minimum short circuit current should be no less than the circuit breaker short circuit setting current 1.3 times;
5) in accordance with the line on the short circuit impact current (namely short circuit all current maximum instantaneous value) to check circuit breaker of rated short circuit making capacity (maximum current expected peak), namely the latter should be greater than the former.
Dc circuit breakerInstall strict inspection before its performance index should comply with the technical requirements.Because if repair quality does not meet the requirements.Such as maintenance change points, switching speed, change breaker arc distance, which made the circuit breaker's breaking capacity to reduce.if ircuit breakerThe breaking capacity is too small;When the short-circuit,Circuit breakeran't cut off short circuit current, cause circuit breaker burst into flames.
Improper operation and maintenance.Dc circuit breakerMany cutting short circuit current, if not timely arrange maintenance but many strong sending, make the circuit breaker many times by the short circuit current impact.These all make circuit breaker block ability is reduced, and thus cause circuit breaker burst into flames.So to strengthen the operation and maintenance and management.Circuit breaker operation, should do patrol inspection work, make circuit breaker normal operation and fault tripping frequency statistics, in order to arrange maintenance time.
Insulating oil not pure.rcuit breaker的。The oil in a lot of free carbide, a large number of aging, oil in tide, water, lead to oil is pure, can make circuit breaker internal happen flashover and cause an explosion.This requires regular insulation test.Especially the thunderstorm season before the preventive test.
In addition peacetime still want to do more preventive maintenance, to ensure that the quality of maintenance.doDc circuit breakerMoistureproof, prevent leakage and pollution prevention work to prevent the circuit breaker water sweat.For these electrical device, such as contactor, choose high quality products is very important, but in the operation of the maintenance and prevent the crisis is more important.
Concludes attention points:Dc circuit breakerRated voltage is equal to or greater than line rated voltage;Circuit breaker undervoltage tripping device rated voltage is equal to rated voltage line;Circuit breaker shunt tripping device is equal to the rated voltage control of the power supply voltage;Dc circuit breakerShell frame levels of rated current is equal to or greater than line calculation load current;Circuit breaker rated current is equal to or greater than line calculation current;Circuit breaker of rated short circuit hige capacity greater than or equal to line the biggest short circuit current;The end of lines single phase short circuit current to earth is equal to or greater than 1.5 times the circuit breaker instantaneous (or short time delay) trip setting current;rcuit breakerType should comply with the installation conditions, protection performance and mode of operation requirements.
Suggestions are as follows:
(1) by the calculation of line current to determine rated current of the circuit breaker,
2) breaker short circuit setting current should avoid line the normal work of the starting current.
(3) the maximum short-circuit current in line to check low voltage circuit breaker's breaking capacity;
(4) according to the line of the minimum short circuit current to check circuit breaker action sensitivity, namely line minimum short circuit current should be no less than the circuit breaker short circuit setting current 1.3 times;
5) in accordance with the line on the short circuit impact current (namely short circuit all current maximum instantaneous value) to check circuit breaker of rated short circuit making capacity (maximum current expected peak), namely the latter should be greater than the former.
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