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| Low voltage electrical appliance use matters needing attention |
| Low voltage electrical circuit breaker selection of different types of short circuit breaking capacity to adapt to different line prospective short-circuit current (when the I in the same condition) need to use principles of circuit breaker is: prospective short-circuit current circuit breaker short-circuit breaking capacity is more than or equal to the line.
1 different load low-voltage electrical appliances should choose different types of circuit breaker
The most common low-voltage electrical load distribution circuit, motor and household and similar household (lighting, household appliances and so on) three categories. Universal type (also known as frame type) DW15 series, in the DW17 circuit breaker (ME) series, AH series and DW45 series DW40, most of B type, and DZ5, DZ15, DZ20, TO, TG, CM1, TM30 and HSM1 series universal type DW15.DW17 and some of the specifications for only overload long delay the two section, instantaneous short circuit protection, they are a circuit breaker belongs to non selection type. Selective protection.
When the F bit short, only close to the point F QF2 circuit breaker operation, and the QF1 circuit breaker on the range of no action, this is the selective protection (QF3.QF4 branch because QF1 does not act, will not fault maintain power supply). If QF2 and QF1 are a class of circuit breaker, F point occurs short circuit, short circuit current value reaches a certain value, QF1.QF2 at the same time, QF1 circuit breaker and its lower branches all the power, it is not selective protection. Can realize the reason of the selective protection, QF1 is B kind of circuit breaker, it has a short delay performance, when the F point short circuit, short circuit current flowing through the QF2 branch, but also through the QF1 loop, the instantaneous tripping device action QF2 (usually it's total breaking time is not more than 0.02s), short delay due to QF1 QF1 0.02s, not in action (in its short delay than 0.1s or 0.2.0.3.0.4s). In the QF2 action to cut off the fault of transmission line, the whole system was restored to normal. Visible, that is to say it can choose a circuit breaker (including plastic shell and universal type). | | | author: Published at: 2015/2/5 10:38:48 |  |
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