scholarly journals AN ELECTRO-MECHANICAL CONTROLLABLE-PITCH PROPELLER

2019 ◽  
Author(s):  
J McBain
Keyword(s):  
Prime Mover ◽  
Axial Motion ◽  
Efficiency Gains ◽  
Rotating Shaft ◽  
Mechanical Coupling ◽  
Mean Time Between Failure ◽  
Hydraulically Actuated ◽  
Mean Time ◽  
Reasoning By Analogy

An electro-mechanical replacement for hydraulically-actuated controllable pitch propellers is described. The proposed mechanism applies a thread to the rotating shaft driven by the ship’s prime mover onto which a ferromagnetic nut is threadedly mated and spun by a stator-born electromagnet; the axial motion of the nut is used to manipulate the pitch of the rotatable blades. The design completely removes any mechanical coupling between the rotor and stator systems. An argument for the mechanism’s efficiency, ease of maintenance, and reduction of weight is provided in the form of reasoning by analogy for the already well studied differentiation between hydraulic and electric cylinders. Efficiency gains of 2-3 times, a doubling of mean-time-between failure, and a reduction of weight by 10% are inferred.

scholarly journals TOTAL PRODUCTIVE MAINTENANCE PADA CHIPER AREA (Study Kasus di PT. Kutai Timber Indonesia Particle Board)

2016 ◽  
Vol 13 (2) ◽  
pp. 1-8
Author(s):  
Arik dwi Hariyanto ◽  
Dwi Iryaning Handayani
Keyword(s):  
Particle Board ◽  
Total Productive Maintenance ◽  
Mean Time Between Failure ◽  
Mean Time To Repair ◽  
Mean Time ◽  
Training Skill

Mesin merupakan komponen utama dalam proses produksi, apabila salah satu mesin mengalami kerusakan maka proses produksi akan berpengaruh, target produksi berkurang, dana untuk perbaikan kerusakan tinggi dan pada akhirnya perusahaan mengalami kerugian. Oleh karena itu perlu dilakukan perawatan mesin secara berkelanjutan agar kerusakan mesin dapat diminimalkan dan fasilitas produksi dapat bekerja sebagaimana yang diharapkan. Penelitian ini bertujuan dapat mengetahui performance maintenance yang diterapkan di PT. Kutai Timber Indonesia Particle Board. Penelitian ini menggunakan konsep Total Productive Maintenance dalam menganalisa terjadinya breakdown mesin pada Chiper Area. Nilai Mean Time Between Failure (MTBF) semakin meningkat sejumlah 112.83 menit sehingga peningkatan keandalannya dikatakan baik sedangkan nilai Mean Time To Repair (MTTR) sebesar 13,88 menit hal ini menunjukkan bahwa kemampuan operator maintenance kurang baik. Nilai Availability mesin mengalami peningkatan sebesar 89%. Dengan demikian perlu dilakukan training skill kepada operator maintenance, dikarenakan hasil MTTR yang didapatkan masih tidak stabil,selain itu perlu menerapkan perawatan mandiri atau small repair pada setiap mesin yang di operasikan, Availability mesin perlu ditingkatkan lagi, dengan nilai availability mesin yang lebih tinggi sehingga meningkatkan produktivitas tanpa mengesampingkan faktor-faktor yang lain. Kata Kunci: Maintenance, Mesin, Produktivitas.

Dynamic characterization of a mechanical coupling for a rotating shaft

2010 ◽  
Vol 225 (3) ◽  
pp. 604-616 ◽  
Author(s):  
A T Tadeo ◽  
K L Cavalca ◽  
M J Brennan
Keyword(s):  
Frequency Response ◽  
Response Functions ◽  
Dynamic Characterization ◽  
Rotating Shaft ◽  
Frequency Response Functions ◽  
Mechanical Coupling ◽  
Lumped Parameter ◽  
Parameter Coupling ◽  
Stiffness And Damping

This article concerns the dynamic characterization of a flexible coupling that connects two co-axial shafts. Four different lumped parameter coupling models from the literature are investigated to see which model could best predict the dynamic behaviour of the coupling. The finite-element method was used to model the rotor dynamic system incorporating the coupling. Frequency response functions from this model were compared with measured frequency response functions from the rotor test rig with the shaft and coupling rotating at a specific speed. Parameters from the model were adjusted to minimize an objective function involving the measured and predicted frequency response functions. It was found that the simplest model of the coupling that could reasonably represent the coupling involves rotational (bending) stiffness and damping.

Foil Air/Gas Bearing Technology — An Overview

1997 ◽  
Author(s):  
Giri L. Agrawal
Keyword(s):  
High Temperature ◽  
Analytical Methods ◽  
High Speed ◽  
Test Results ◽  
Air Bearings ◽  
Mean Time Between Failure ◽  
Foil Bearing ◽  
Cryogenic Liquids ◽  
Gas Bearing ◽  
Mean Time

This paper summarizes the chronological progress of foil air bearings for turbomachinery during the last 25 years. Descriptions of various machines which are in production are provided. The foil bearing air cycle machine on the 747 aircraft has demonstrated an MTBF (mean time between failure) in excess of 100,000 hours. Many advantages of foil air bearings are noted. Various designs of foil air bearings presently in use and their relative merits are described. Analytical methods, their limitations, and their relationships with test results are noted. Descriptions of various machines built and tested in process fluids being gases, other than air, and cryogenic liquids are described. Conclusions are drawn that various high speed turbomachines including high temperature applications can be designed and developed using foil air bearings which will increase efficiency and reduce cost of these machines.

scholarly journals Perencanaan Perawatan Mesin Welding Mig Pada Produksi Sub Frame Di PT. XYZ Dengan Metode Reliability Centered Maintenance (RCM)

2021 ◽  
Vol 6 (1) ◽  
pp. 26-38
Author(s):  
Zulkani Sinaga ◽  
Solihin Solihin ◽  
Mochamad Ardan
Keyword(s):  
Failure Mode ◽  
Time To Failure ◽  
Risk Priority Number ◽  
Mean Time To Failure ◽  
Effect Analysis ◽  
Mean Time Between Failure ◽  
Reliability Centered Maintenance ◽  
Mean Time To Repair ◽  
Mean Time

Pemeliharaan merupakan suatu proses yang dilakukan untuk menjaga keandalan, ketersediaan dan sifat mampu merawat komponen atau mesin. Program pemeliharaan yang efektif dan efisien akan mendukung peningkatan produktifitas sistem produksi. PT. XYZ merupakan perusahaan nasional bergerak dibidang karoseri truck mengalami penurunan produktivitas disebabkan belum adanya strategi perawatan khususnya mesin welding jenis MIG sehingga sering terjadi downtime mesin mengakibatkan proses produksi menjadi terhambat. Berdasarkan alasan tersebut dibutuhkan program pemeliharaan yang efektif dan efisien dengan menerapkan analisis menggunakan metode  Reliability Centered Maintenance (RCM) guna menciptakan metode pemeliharaan yang akurat, fokus, dan optimal dengan tujuan mencapai keandalan yang optimal. Penelitian dilakukan dengan mengikuti langkah-langkah perhitungan berdasarkan Failure Mode and Effect Analysis (FMEA) dan penetapan strategi pemeliharaan dengan dibantu menggunakan software minitab 18. Hasil penelitian diperoleh Risk Priority Number (RPN) untuk komponen wire feeder sebesar 611, dengan pola distribusi waktu normal, nilai parameter median 61,9391 dan standar deviasinya 48,6053, nilai Mean Time To Failure (MTTF) sebesar 61,9391 jam dan selang interval waktu penggantian komponen sebesar 10,1349. Berdasarkan hasil perhitungan performance maintenanace diketahui nilai Mean Time Between Failure (MTBF) antara 31,92 ~ 72,09 jam, Mean Time To Repair (MTTR) anatara 1,19 ~ 1,78 jam dan availability antara 94,67% ~ 98,24%, setelah dilakukan tindakan perawatan pencegahan selama periode tersebut dihasilkan nilai availability sebesar 98,01% artinya kerusakan pada komponen wire feeder dapat teratasi.

An Investigation in to the Rotordynamics Behavior of Mechanically Coupled Turbo Expander

2014 ◽  
Author(s):  
Balaji Kannan ◽  
Krishnamurthy Vaidyanathan ◽  
Kiran Pithamber ◽  
Suvendu Mahapatra
Keyword(s):  
High Speed ◽  
Reduction Gear ◽  
Experimental Investigations ◽  
Prime Mover ◽  
Damping Properties ◽  
Mechanical Coupling ◽  
Lateral Vibrations ◽  
Multi Stage ◽  
Turbo Expander ◽  
The Impact

Considerable amount of mathematical modeling backed by extensive experimental investigations have gone in to the study of the rotordynamics behavior of high speed turbo expanders. These investigations revolve predominantly around the linear & non-linear aspects of hydrodynamic bearings that support these rotating elements. Further, these expanders are not mechanically coupled to the prime mover and hence the impact of lateral vibrations imposed by the interfacing assemblies downstream is not a concern. However, when the expander is mechanically coupled to a prime mover, say by means of gears, lateral vibrations resulting from the interfacing system is going to have a pronounced effect on the rotordynamics behavior of this system. It is of paramount importance that we account for the stiffness & damping properties of the interface components in order to accurately predict the rotordynamics behavior of the expander. An attempt is being made by the authors to develop an expander and bearing system along with a high speed, multi stage reduction gear box, to understand the impact of lateral vibrations due to mechanical coupling of the expander.

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