It is estimated that (85-95%) of the electric motor
failures occur due to damage to the stator winding. In
this case, more than 90% of damage are because of
interturn short circuits. Short circuits in stator windings
of stand-alone asynchronous generator change the base
magnetic flux incidentally, so the probability of its long
work with such kind of damage is great. A latent
failure, existing as a loop closure, significantly reduces
the reliability of the generator as a backup power
source. Now sensitive protections of asynchronous
generators do not exist, since it is believed that in the
case of short circuits (short circuit), the generator loses
its excitation, and protection is not required for it.
Identification of information signs of short-circuit
currents in the stator winding of an asynchronous
generator makes it possible to develop relay protection.
The main principle of detection of stokes closures in
the stator winding of an asynchronous electric motor is
the measurement of the emerging asymmetry of the
stator currents. It has been established that in the case
of short-circuit faults, the asymmetry of the currents
and voltages is not large and comparable to the
asymmetry in the AAG load circuit. This does not
allow performing a protection that reacts to this
asymmetry. You can also say about changing the
harmonic spectrum of currents and voltages. To build
protection, it is necessary to use highly sensitive
circuits for detecting the asymmetry of a three-phase
system of currents and voltages, as well as distortion of
the shape of currents and voltages, for example, by
harmonic analysis. Do not exclude the possibility of
using other protection devices, such as reacting the
vibration of the case of an induction generator in the
event of damage to the stator winding
The electric method of gas dedusting is the most
effective, since it allows capturing solid particles with
a size from 0.01 µm to tens of microns. The efficiency
of dust and gas cleaning equipment of Novocherkassk
SDPP for cleaning flue gases from ash at power units
1-7 in the period from February 2015 to February 2017
is considered. The main equipment is electrostatic
precipitators. As a solid fuel, Donetsk culm is used. It
is established that the efficiency of waste gas
purification at power units 5-7 was about 99 %, while
at power units from the 1st to the 4th this value was
within 95-96 %. The data obtained correspond to the
design data, but it is recommended that the cleaning
devices be improved to improve their efficiency. The
most acceptable is a combined electrofilter-bag filter
The market for functional food products is continuously
increasing and, according to analysts, by 2020 its
share will reach 40% of all food products. The development
of the healthy food has been gathering momentum
in recent years, the search for non-traditional
types of raw materials is constantly being conducted,
and new recipes for products enriched with natural
food additives are being created. In this regard, special
attention is paid to the production and use of powdered
food additives from plant raw materials. Theoretical
significance and practical applicability of powder
technologies in different years was substantiated by
such famous scientists as Deryagin B.V., Donchenko
L.V., Zimon A.D., Zubchenko A.V., Kasyanov G.I.,
Magomedov G.О., Paschenko L.P., Rebinder P.A.,
Tilesnik M.A., Yankhin E.D. In their opinion, using
natural food additives, it is possible to obtain functional
food products with specified chemical composition
and properties. The objects of our research were apricot,
grape seeds, pumpkin flesh, black currant and seabuckthorn
berries, spinach, apples and flour from lowfat
barley. In the course of the study, the effect of dispersity
of the obtained powders on their antioxidant
activity and frictional properties was studied. The expediency
of introducing powders into the composition
of multicomponent food products for enriching them
with carbohydrates, vitamins and microelements is
shown. The organoleptic evaluation of the produced
powders showed that they have high taste values. The
study of organoleptic and microbiological indices of
products enriched with such powders indicates prolongation
of their shelf life. As the main results of the study, we note the assessment of the chemical composition
of the powders from the investigated objects, as
well as the improvement of the technology of drying of
plant raw materials with sparing technological regimes
of its implementation
The present level of development of power systems,
the need to increase their resources and increased
competition have caused especially true problem of
increasing the efficiency of their operation. The work
is devoted to the justification of the selection and
development of a technique of construction of the
diagnostic model to search for failures in power
objects
According to its operating principles, generators of
aircraft electric power supply systems do not differ
from the similar generators of transporting and
stationary systems, but have range of peculiarities:
low weight and dimensions, high density of armature
current, compulsory cooling (air and liquid), high
frequency of rotor spinning. The article considers main
requirements, imposed to generators of flight vehicle
and the construction peculiarities and main physical
and operational characteristics of generators applied in
modern flight vehicles. It is suggested to use noncontact
electrical machines as sources of electrical
energy in the aircraft electric power supply systems:
synchronous generators with impulses from permanent
magnets and asynchronous generators with capacitive
impulse. To improve physical and operational
characteristics of generators and aircraft electric power
supply systems it is suggested to refuse from
permanent frequency spinning drivers which have low
converters as stabilizer of voltage and frequency
current of electrical energy source. The peculiarities of
its operation are considered, its advantages and
disadvantages. It is possible to improve characteristics
of aircraft electric power supply systems by means of
study of the electromagnetic compatibility of the main
functional system elements and by means of
application of non-contact electrical devices, applied in
the guard and control systems, made on the basis of
power and electronic devices
The ways of improving the work of food enterprises during processing of agricultural raw materials on the basis of a system analysis of the durations of technological operations are considered. The basic mathematical models of technological processes have been analyzed and the possibility of using unified technological operations to predict the time of completion of work has been shown for processing various pairs of raw materials. It is established that the construction of mathematical models of technological processes of processing of agricultural raw materials should be based on using the potential of transfer of the target component between isopotential surfaces. This allows not only to unify the created models of technological processes, but also to significantly increase their extrapolating ability to estimate the durations of technological operations
An overview of various ways of preparing roses for
industrial processing with the aim of obtaining rose
essential oil is presented. Based on the patent and
information retrieval data, features of new, scientific
developments in this field, which have not yet found
wide application in industrial processing, their
advantages and disadvantages are discussed. The
conclusion is made about the need to search for new,
modern, environmentally safe ways of preparing raw
essential oil for industrial processing
To reduce the development of additional settlement
strip foundations of the existing building on the effect
of pressure transmitted to a ground base located near
the new slab foundation is considered the work of the
geotechnical barrier in various ground conditions. In
the first variant of soil, conditions (variant 1) made
geotechnical barrier structure in a homogeneous
thickness of the weak clay soil. In the second variant
of soil conditions (variant 2), a separating barrier is
performed in a two-layer base. The upper base layer
(carrying) is shown a weak water-saturated clay soil,
and the second (underlying) - low compressible soil
(sandy loam plastic). According to the results of the
calculations and modeling found that, the greatest
positive effect on the separating barrier structure
(geotechnical barrier) is achieved in the case when the
base is a two-layer. The lower part of the geotechnical
barrier must be recessed into the soil of low
compressibility. Additional settlement strip foundation
of the existing building in a uniform basis (variant 1)
in the absence of geotechnical barrier is approximately
8 cm. In the case of a two-layer base (variant 2), the
additional settlement strip foundation building is
reduced by 80-85% (6.6 cm) and will make about 1.4
cm
The power plant being investigated is Novocherkassk
State District Power Plant located in the settlement of
Donskoy, Rostov region. The power object is included
in the list of objects of the fuel and energy complex
subject to categorization and is defined as critically
important. The analyzed site is the "subsidiary farm",
which includes a chemical reagent warehouse and a
site for chemical water purification, where hazardous
substances are treated: sulfuric acid and technical
sodium hydroxide. The analysis of the main causes of
accidents at thermal power stations occurred during
processing, storage and transportation of hazardous
substances, and typical scenarios of possible accidents
at the chemical water treatment plant of thermal power
plants were considered
The competitiveness of any company engaged in the
wholesale or retail sale of goods and services is
substantially determined by the level of quality of the
services provided. For the accompanying business of
vertically integrated oil companies, the criterion of
quality service is not an exception. Currently, cafes
and shops at the refueling complex are not only a
convenient service for customers, but also a solid
source of additional revenues for the largest oil
companies, each of which seeks to make the retail
network attractive to customers by offering a wide
range of goods in stores, ready meals in a cafe, and
related services. To satisfy the needs of the client, it is
necessary to offer a wide, but rational assortment of
goods at the refueling complexes. The claimed goods
must always be at the refueling complexes. The lack of
goods necessary for the customer on the shelf means
the loss of sales and profits, the order and location of
goods that are not in demand - the formation of
surpluses, returns to the supplier and write-offs. This
also affects the overall economic performance of the
company. In this regard, the increase of logistics
service is one of the priority tasks of the
accompanying business of vertically integrated oil
companies