Günümüzde, orta ve yüksek frekanslar, makine boyutunda önemli derecede küçülme saðlamasýna raðmen bu frekanslardan kaynaklanan kayýplarý da beraberinde getirmektedir. Elektrik makinalarýnda meydana gelen kayýplar özel sargý tasarýmlarý ile azaltýlabilmektedir. Bu çalýþmada ayný kesitteki tek damarlý iletken, litz iletken ve bakýr folyo iletken kayýplarý sonlu elemanlar yöntemi ile incelenmiþtir. Ayrýca frekansýn deðiþimine baðlý olarak iletkenlerdeki akým yoðunluðu, manyetik aký yoðunluðu ve omik kayýplar bir tasarým programý yardýmýyla incelenmiþ ve elde edilen grafikler verilmiþtir.

Today, although medium and high frequencies have been provided a significant reduction in the size of machine, it is known that as the more frequency increases, the higher losses at conductors. In this study, wire losses of the same cross section but different structures are examined by finite elements method. Also, depending on the exchange rate in wires at conductors, changes of current density, magnetic flux density and ohmic losses were investigated. The use of different structured wires of conductors at different frequencies has been compared in terms of their losses, and given the graphics regarding to the design by special design software.

Bu çalýþmada, Gökçeada/Türkiye’de yerleþik ve þebekeden baðýmsýz
2 kW anma gücündeki bir fotovoltaik (FV) güç sisteminin benzetim ve uygulamalý baþarým analizi yapýlmaktadýr. Sistemin baþarýmý, hem benzetim hem de gerçek zamanlý ölçüm deðerleri kullanýlarak incelenmiþtir. Benzetim çalýþmasýndan hesaplanan % 5 sistem verimi ve % 41 gerçekleme oraný parametreleri, gerçek çalýþma koþullarýnda izleme dönemi ortalamasý olarak sýrasýyla % 4 ve % 32,4 olarak gerçekleþmiþtir. Bu çalýþmada, uluslararasý deðerlendirme parametreleri dikkate alýnmýþtýr. Benzetim ve gerçek zamanlý baþarým deðerleri arasýndaki farkýn temel gerekçesi kýsmi gölge etkileri ve belli dönemlerde düþük yük talebinin üstünde üretilen enerjinin sýnýrlanmasý olarak gözlenmiþtir.

This study simulates and analyzes the practical performance of a 2 kW stand-alone PV power system located in Gökçeada/Turkey. System performance was calculated both by simulation and real life measurements. Although the total system efficiency and the performance ratio is simulated 5 % and 41 %, these values are calculated averagely during the real-life monitoring period as 4 % and % 32.4 respectively. The results were reported using the international evaluation parameters. The main reasons of the difference between the simulated and practical calculated values are the partial shadow effects and the limited energy generation due to the low load demand.

Bu makalede, yürüyen dalga ultrasonik motor için sayýsal denetimli kompakt bir hýz sürücüsü tasarlanmýþ ve gerçekleþtirilmiþtir. Sürücü basit, hafif ve küçük olmakla beraber ultrasonik motorun hýz ve yön komutlarý sayýsal olarak girilirken gerçek motor hýzý, gerilimi ve akýmý bir display üzerinden izlenebilmektedir. Gerçekleþtirilen sayýsal denetimli sürme sisteminin deneyleri deðiþik hýz ve yük þartlarýnda laboratuarda yapýlmýþ ve elde edilen sonuçlar sunulmuþtur.

In this paper, a compact size digitally controlled speed driver for travelling wave ultrasonic motor was designed and implemented. Although the driver system is light in weight, simple, small in size, it is possible to enter speed and direction digitally as well as tracking the real motor speed, voltage and current on an LCD. The implemented system was tested in a laboratory for different speed and load cases and obtained results are presented.

When compared with the other transportation systems, railway systems are economical, safer and more environment friendly. Despite all these features, investments on railways in Turkey remained quite restricted in comparison to other European countries. The initial construction costs of railways are high and developing its signaling system also requires a lot of attention. Signaling system is the vital part of a railway system which ensures safe travel and transportation on railways. One of the main reasons that make a signaling system critical and hard to develop is to satisfy the recommendations of related functional safety standards such as EN 50128 and EN 61508-3. In this study, functional safety requirements used in railway signaling systems are stated and the use of recommended methods in the Turkish National Railway Signaling Project (TNRSP) are explained. Especially, the software development process and the use of several programming techniques in determination of the software architectures are discussed.

Bu çalýþmada, Pamukkale Üniversitesi Mühendislik Fakültesi Jeoloji Mühendisliði Bölümü bünyesinde tasarlanmýþ ve bir üretici firmaya yaptýrýlmýþ olan 1.5x1.0 m ebatlarýndaki sarsma masasý tanýtýlmýþ ve üretilebilen hareket parametrelerine deðinilmiþtir. Farklý mühendislik amaçlarý doðrultusunda, depremlerin etkisiyle meydana gelen dinamik etkinin laboratuvar koþullarýnda modellenebilmesi için sarsma masalarý kullanýlmaktadýr. Büyük boyutlu sarsma masalarý, yüksek güç kapasiteli ve çok hýzlý hareket edebilen hidrolik sistemlerle çalýþmakta ve çok yüksek maliyetlere ulaþmaktadýr. Bunun yanýnda küçük boyutlu ve üzerinde çeþitli model deneylerinin yapýlabildiði ve farklý eðitim amaçlarý doðrultusunda kullanýlabilen düþük maliyetli sarsma masalarý yaygýn olarak kullanýlmaya baþlamýþtýr. Bu çalýþmada tanýtýlan tek yönlü, hareketini elektrik motorundan alan sarsma masasý ile elde edilebilen, hýz, ivme, frekans ve periyot deðerlerine deðinilmiþtir. Örnek bir uygulama olarak laboratuvar koþullarýnda artan taban ivmesi etkisinde düzlemsel kayma yüzeyi içeren ve doðal malzeme ile oluþturulmuþ bir bloðun kayma hareketi izlenmiþtir. 3 farklý eðim miktarý için deney tekrarlanmýþtýr. Harekete neden olan kritik ivme deneysel olarak belirlenmiþ ayrýca sayýsal olarak hesaplanarak ölçülen ve hesaplanan deðerler karþýlaþtýrýlmýþtýr.

In this study, 1.5x1.0 m dimensioned shaking table which was designed and built by Geological Engineering Department of Pamukkale University Engineering Faculty is introduced and produced motion parameters are discussed. In order to determine the different engineering purposed model behaviors under earthquake induced dynamic loads, shaking tables are used in laboratory conditions. High power capacity and fast hydraulic systems are needed for large shaking table facilities and this makes them very expensive. However small scaled economical shaking tables are getting used in different purposes such as model tests and educational demonstrations. Velocity, acceleration, frequency and period values of this electric motor driven unidirectional shaking table which was introduced in this study were calculated. Finally as an example application, a block which is consisted of natural material and has a planar sliding surface, attached on shaking table and displacement of the block with increasing base acceleration was monitored. Critical acceleration for the sliding block was experimentally determined. Tests were repeated in three different slope angles. Displacements were also calculated and measured and calculated block displacement values were compared.