Technological process of a coal mining in a clearing face is the basic process in technology of a underground coal mining on mine. The degree of use of the equipment of all subsequent technological processes, economic parameters of the enterprise depends on its rhythmical work in many respects. Automation of productions is especially actual for a mining industry which tests constant complication of conditions of extraction of the mineral, free occurrenced with transition to development of bed with smaller capacity and on deeper horizons.
Creation of the device with automatic control of isolation resistance of a mine electric equipment and also, designing of automation system which definition a place of mine cable damage is necessary problem.
The major task of work is application of modern diagnostic technical equipment revealing on an early stage defects and predisposition to damage isolation.
Planned scientific novelty is development of the device of the automatic control of resistance of isolation of a mine electric equipment on the one of microcontrollers from family Atmel.
Practical value will be prospective introduction of development in technical samples of verifying technics.
The least reliable compound unit of the asynchronous engine with a short-circuited rotor is the winding stator. From a sight of reliability it represents system, all its componentry is logically consecutive co-operative also reservation is absent, therefore the opportunity of absence of breakdown of a winding of common industrial and hardened asynchronous engines makes:
Hob(t) = HB(t) Hk(t) Hmf(t) , (1)
where HB(t) – probability of absence of breakdown ring isolation; Hk(t) - probability of absence of breakdown of case isolation; Hmf(t) - probability of absence of breakdown of interphase isolation.
From here the average resource of a winding stator of the asynchronous engine before major overhaul Tob.do is defined under the formula:
Tob.do = Hob(t) d t, (2)
As the parameter describing isolation durability, the penetrative voltage uïð its element in view of its change is accepted at ageing, and describing loading – submitted to an element voltage.
Distribution of a penetrative voltage of the isolation elements of windings will be coordinated with distribution to type I for the minimal members of variational series. From here, the probability of absence of breakdown of the given kind of isolation of a stators winding (ring, case or interphase) is defined under formulas:
Hi = CHi e xp (-exp Guzi), (3)
Hi = CHi e xp (-exp Guzi), (4)
G uzi = B uzi (Ki* Kkf* M* 1,41* uf-guzi), (5)
guzi = Kump * ui (t) + Gm/B uzi, (6)
b uzi = Gm / Si (t), (7)
ui (t) = uo * Kv , (8)
Si(t) = So * Ks, (9)
where G uzi - normalized variable; Ki - an average of overvoltage; ui - an average penetrative voltage of isolation; Si - an average rejection of voltage; M - the factor considering a level of the influencing voltage which brought on pair close located coils pouring coil, and also influence of defects of ring isolation at the given voltage in working; Kump - factor of pulse durability of isolation; uzi , guzi- parameters of distribution I-th type of a voltage of isolation; m ,Gm- tabulared average value and an average square-law rejection of normalizing function of distribution I-th type;