News of network of global electric machinery: The fundamental that capacity of dynamo of   ? chooses reachs relevant element; Build model of capacity calculative maths; The QBASIC source program that place of introductory computation capacity uses reachs his to operate a point; Gave out to be like dry conclusion and computational example finally. Key word: Bear of derv dynamo fire control makes sure bear is concessional voltage drop starts desired result

1 foreword

In building of contemporary high level, choice derv generation set serves as reserve power source, already belonged to common; The academic implied meaning that about its the capacity determines, also see repeatedly at the press. But in actual project application, a lot of design personnel still have do not have the foreword, feeling that expends setbacks quite absently. After all how capacity of dynamo of computation of fast and accurate ground, it is the main task that is worth to discuss all the time. The article will be emphasized with process designing of computer of a paragraph of QBASIC, solve this one problem more handily.

2 fundamental

2. 1 dynamo capacity should satisfy stable computation bear to need above all, this includes fire protection bear and assure bear two parts. In civil building, set derv generation set, it is to serve as what fire control uses electric device to reserve above all normally power source. Town report power cut, namely interlocking open generation set. But probability of town report power cut is ambitious at fire probability, open aircrew does not mean fire to happen. When be not fire control, the generation set of open is mere the fraction bear such as burden lash-up illume, the main negative charge that is like pair of other blame fire control (illume of ladder of the life pump when belonging to 3 kinds of bear, guest, annex, call assure bear) cannot attend to, be sure to create waste of aircrew empty buy, resources. For this, when undertaking graph of low-pressure distribution system is designed, below the premise that when contented fire fire control bear needs, when still must considering fire of power cut and rather than, the dynamo is right the power supply that assures bear. A kind of practice is, will make sure bear is hanged centrally receive go up in line segment of dynamo lash-up mother, when fire control, divide the master switch that assures bear encourage to take off by fire signal buckle. Anyhow, part of one's job is not calculated fire control bear and assure bear, with both greater value regards affirmatory generation set as the basis of the capacity, satisfy fire control branch and construction at the same time thereby square corresponding requirement.
How is fire control bear calculated correctly should cause take seriously. Large and medium-sized civil building, often comprise by basement, annex and several tower, included partition of many fire prevention. Affirmatory dynamo capacity, when undertaking fire control bear is calculated, cannot use all fire control electric equipment to be entered with chronometer blindly apparently. Commendatory computational principle is, consider partition of a fire prevention to produce fire only (fire protection of water of no less than is same) , i.e. , the fire prevention partition that does not think two reach above is coinstantaneous fire. Normally, fire pump serves as fixed negative charge must plan into, and fire lift, prevent illume of smoke extractor exhaust fan, lash-up to wait for bear plan how to much enter, the bear size that should inspect its to throw a service when fire of partition of some fire prevention and calm. Apparent, determine dynamo size, should when with worst partition of a fire prevention produces fire, the fire control negative charge that at the same time investment runs is accurate.
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