A Forecasting Technique for Operational Reliability (MTBF) and Maintenance (MMH/FH)

1977 ◽  
Author(s):  
William C. Widenhouse ◽  
William E. Romans
Keyword(s):  
Operational Reliability

Influence of unbalanced magnetic force on shaft deflection in permanent magnet synchronous motor with fractional slot concentrated windings

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1461-1468
Author(s):  
Ting Dong ◽  
Juyan Huang ◽  
Bing Peng ◽  
Ling Jian
Keyword(s):  
Permanent Magnet ◽  
Magnetic Force ◽  
Permanent Magnet Synchronous Motor ◽  
Operational Reliability ◽  
Topology Structure ◽  
Permanent Magnet Synchronous Motors ◽  
Synchronous Motors ◽  
Shaft Deflection ◽  
Large Length ◽  
Fractional Slot

The calculation accuracy of unbalanced magnetic forces (UMF) is very important to the design of rotor length, because it will effect the shaft deflection. But in some permanent magnet synchronous motors (PMSMs) with fractional slot concentrated windings (FSCW), the UMF caused by asymmetrical stator topology structure is not considered in the existing deflection calculation, which is very fatal for the operational reliability, especially for the PMSMs with the large length-diameter ratio, such as submersible PMSMs. Therefore, the part of UMF in the asymmetrical stator topology structure PMSMs caused by the choice of pole-slot combinations is analysized in this paper, and a more accurate rotor deflection calculation method is also proposed.

IMPROVEMENT OF THE OPERATIONAL RELIABILITY OF THE BOTTOM OF VERTICAL STEEL TANKS FOR OIL AND PETROLEUM PRODUCTS

2019 ◽  
pp. 59-65 ◽  
Author(s):  
V.A. Yudakov ◽  
◽  
S.D. Fan ◽  
I.A. Fan ◽  
M.R. Teregulov ◽  
...  
Keyword(s):  
Petroleum Products ◽  
Operational Reliability ◽  
Steel Tanks

Experience with Vortex Separators for Combined Sewer Overflow Control

1993 ◽  
Vol 27 (5-6) ◽  
pp. 93-104 ◽  
Author(s):  
H. Brombach ◽  
C. Xanthopoulos ◽  
H. H. Hahn ◽  
W. C. Pisano
Keyword(s):  
Separation Efficiency ◽  
Operational Reliability ◽  
Second Phase ◽  
Combined Sewer Overflow ◽  
Specific Storage ◽  
Impervious Area ◽  
Evaluation Phase ◽  
Combined Sewer ◽  
Sewer Overflow ◽  
Overflow Control

In 1987 the first vortex solids separator facility in Germany was installed for combined sewer overflow (CSO) control. The separation efficiency was optimized in the hydraulic laboratory using scaled down models with artificial tracers to simulate typical sewage particulates. The station has two parallel operating vortex separators and serves a connected and impervious area of about 11 hectares (ha) and 1,500 people. The specific storage volume of the station is 7.2 m3 per ha. Two evaluation programs were conducted. The first evaluation phase noted the operational reliability, hydraulic loads, overflow frequencies and water mass balances. The second phase monitored separation efficiencies. The evaluation showed that vortex solids separators are now ready for use in CSO control.

Two-Phase Short Circuit in the Power Grid Powered by a Transformer with a Y/Δ-11 Winding Connection

2020 ◽  
pp. 25-30
Author(s):  
Aleksandr S. Serebryakov ◽  
Vladimir L. Osokin ◽  
Sergey A. Kapustkin
Keyword(s):  
High Speed ◽  
Short Circuit ◽  
Relay Protection ◽  
Electric Circuit ◽  
Operational Reliability ◽  
Research Purpose ◽  
Industrial Complex ◽  
Two Phase ◽  
Short Circuit Currents ◽  
Secondary Winding

The article describes main provisions and relations for calculating short-circuit currents and phase currents in a three-phase traction transformer with a star-triangle-11 connection of windings, which feeds two single-phase loads in AC traction networks with a nominal voltage of 25 kilovolts. These transformers provide power to the enterprises of the agro-industrial complex located along the railway line. (Research purpose) The research purpose is in substantiating theoretical equations for digital intelligent relay protection in two-phase short circuits. (Materials and methods) It was found that since the sum of instantaneous currents in each phase is zero, each phase of the transformer works independently. We found that this significantly simplifies the task of analyzing processes with a two-phase short circuit. In this case, the problem of calculating short-circuit currents in the traction network can be simplified by reducing it to the calculation of an ordinary electric circuit with three unknown currents. (Results and discussion) The article describes equations for calculating short-circuit resistances for one phase of the transformer when connecting the secondary winding as a star or a triangle. The currents in the phases of the transformer winding at short circuit for the star-triangle-11 and star-star-with-ground schemes are compared. It was found that when calculating short-circuit currents, there is no need to convert the secondary winding of the traction transformer from a triangle to a star. (Conclusions) It was found that the results of the research can be used in the transition of relay protection systems from electromagnetic relays to modern high-speed digital devices, which will increase the operational reliability of power supply systems for traction and non-traction power consumers.

FMEA method in operational reliability of forest harvesters

2020 ◽  
Vol 11 (1) ◽  
pp. 29-38
Author(s):  
Ján Kováč ◽  
Pavol Ťavoda ◽  
Jozef Krilek ◽  
Pavol Harvánek
Keyword(s):  
Failure Mode ◽  
Working Conditions ◽  
Operational Reliability ◽  
Human Potential ◽  
Information Analysis ◽  
Effect Analysis ◽  
Operational Conditions ◽  
Its Analysis ◽  
Fmea Method ◽  
Operational Data

AbstractThe article deals with the research of operational reliability of forest felling machines by FMEA method (Failure Mode and Effect Analysis). It describes collection of operational data and its analysis. It explains the procedure of realization for the method FMEA in the organization. Harvesters John Deere 1070D in the Company Lesy SR B. Bystrica were chosen for this research. The research was held in real operational conditions. Application of the FMEA method allows flexibility in case of unexpected situations and optimization of human potential abilities. FMEA tool is a tool preventing outages operational reliability and preventive tool for ensuring the maintenance of facilities. The method of information analysis mentioned below is simple ale precise enough for implementation in real working conditions.

scholarly journals Design Optimization of Centrifugal Microfluidic “Lab-on-a-Disc” Systems towards Fluidic Larger-Scale Integration

2021 ◽  
Vol 11 (13) ◽  
pp. 5839
Author(s):  
Jens Ducrée
Keyword(s):  
Design Optimization ◽  
Retention Rate ◽  
Point Of Care ◽  
Operational Reliability ◽  
Band Width ◽  
Disc Space ◽  
Laboratory Unit ◽  
Digital Twin ◽  
Point Of Use ◽  
Scale Integration

Enhancing the degree of functional multiplexing while assuring operational reliability and manufacturability at competitive costs are crucial ingredients for enabling comprehensive sample-to-answer automation, e.g., for use in common, decentralized “Point-of-Care” or “Point-of-Use” scenarios. This paper demonstrates a model-based “digital twin” approach, which efficiently supports the algorithmic design optimization of exemplary centrifugo-pneumatic (CP) dissolvable-film (DF) siphon valves toward larger-scale integration (LSI) of well-established “Lab-on-a-Disc” (LoaD) systems. Obviously, the spatial footprint of the valves and their upstream laboratory unit operations (LUOs) have to fit, at a given radial position prescribed by its occurrence in the assay protocol, into the locally accessible disc space. At the same time, the retention rate of a rotationally actuated CP-DF siphon valve and, most challengingly, its band width related to unavoidable tolerances of experimental input parameters need to slot into a defined interval of the practically allowed frequency envelope. To accomplish particular design goals, a set of parametrized metrics is defined, which are to be met within their practical boundaries while (numerically) minimizing the band width in the frequency domain. While each LSI scenario needs to be addressed individually on the basis of the digital twin, a suite of qualitative design rules and instructive showcases structures are presented.

Remaining useful life prediction method for machine tools based on meta-action theory

2021 ◽  
pp. 1748006X2110025
Author(s):  
Zongyi Mu ◽  
Yan Ran ◽  
Genbao Zhang ◽  
Hongwei Wang ◽  
Xin Yang
Keyword(s):  
Machine Tools ◽  
Life Prediction ◽  
Action Theory ◽  
Prediction Method ◽  
Operational Reliability ◽  
Remaining Useful Life ◽  
Practical Application ◽  
Dynamic Prediction ◽  
Degradation Model ◽  
Useful Life

Remaining useful life (RUL) is a crucial indictor to measure the performance degradation of machine tools. It directly affects the accuracy of maintenance decision-making, thus affecting operational reliability of machine tools. Currently, most RUL prediction methods are for the parts. However, due to the interaction among the parts, even RUL of all the parts cannot reflect the real RUL of the whole machine. Therefore, an RUL prediction method for the whole machine is needed. To predict RUL of the whole machine, this paper proposes an RUL prediction method with dynamic prediction objects based on meta-action theory. Firstly, machine tools are decomposed into the meta-action unit chains (MUCs) to obtain suitable prediction objects. Secondly, the machining precision unqualified rate (MPUR) control chart is used to conduct an out of control early warning for machine tools’ performance. At last, the Markov model is introduced to determine the prediction objects in next prediction and the Wiener degradation model is established to predict RUL of machine tools. According to the practical application, feasibility and effectiveness of the method is proved.

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