ВЫБОР ДОПУСТИМЫХ СЕЧЕНИЙ ЭЛЕКТРИЧЕСКИХ ПРОВОДОВ И КАБЕЛЕЙ В БОРТОВЫХ ЦЕПЯХ ЭЛЕКТРООБОРУДОВАНИЯ ЛЕТАТЕЛЬНЫХ АППАРАТОВ

Purpose. Implementation of choice of maximum permissible sections S il of the uninsulated wires and insulated wires (cables) with copper (aluminum) cores (shells) in the on-board power circuits of electrical equipment of different aircrafts with AC current of frequency f>50 Hz. Methodology. Theoretical bases of the electrical engineering, electrophysics bases of technique of high voltage and high pulsed currents, applied thermal physics. Results. The engineering approach is developed for a calculation choice on the condition of thermal resistibility of aircraft cable-conductor products (CCP) of maximum permissible sections S il of the uninsulated wires, insulated wires and cables with copper (aluminum) cores (shells), polyvinyl chloride (PVC), rubber (R) and polyethylene (PET) insulation, on which in malfunction of operation of on-board aircraft network with AC frequency of f>50 Hz flows of i k (t) current at single phase short circuit (SC) with given amplitude-temporal parameters. It is determined that in the on-board power circuits of electrical equipment of aircrafts (f=400 Hz; for permanent time of slump of T a =3 ms of аperiodic constituent of current of SC) maximum permissible amplitudes of current density of δ ilm ≈I mk /S il of single phase SC at time of its disconnecting t kC =5 ms in the on-board network of aircraft without dependence on the numerical value of amplitude I mk of the given current of SC for the uninsulated wires with copper (aluminum) cores is accordingly about 2.48 (1.40) kA/mm 2 , for wires (cables) with copper (aluminum) cores (shells) and PVC (R) with insulation – 1.85 (1.18) kA/mm 2 , and for wires (cables) with copper (aluminum) cores (shells) and PET insulation – 1.53 (0.99) kA/mm 2 . The influence on a choice in the on-board network of aircrafts of maximum permissible sections S il of its CCP and accordingly maximum permissible amplitudes of current density δ ilm of current copper (aluminum) parts of its wires and cables of frequency f of AC in the on-board network of aircraft is determined, but duration of flow t kC (time of disconnecting) renders in the on-board network of aircrafts of emergency current of SC i k (t. For diminishing in the on-board power circuits of electrical equipment of aircrafts of maximum permissible sections S il of the electric wires (cables) applied in them and accordingly providing of decline for different aircrafts of mass and overall indicators of their on-board CCP is needed in the on-boar networks of aircrafts along with the use of enhance frequency of f=400 Hz of AC to apply the fast-acting devices of their protecting from SC in course of time wearing-outs of t a <<100 ms. It isshown that application of enhance frequency of f=400 Hz of AC in the on-board networks of aircrafts as compared to its frequency of f=50 Hz results in the considerable increase (in four times) of fast-acting of devices of their protection from SC, operation of which is based on the air electric explosion of metallic wire. Originality. First for the on-board network of aircrafts with AC of frequency of f=400 Hz the maximum permissible sections S il and amplitudes of current density  δ ilm of SC are determined for the uninsulated wires and insulated wires (cables) with copper (aluminum) cores (shells), PVC, R and PET insulation. Practical value. Theobtained results will be used in the increase of thermal resistibility of CCP with copper (aluminum) cores (shells), PVC, R and PET insulation applied in the on-board electric networks of different aircrafts.