Scientific Journal of Gdynia Maritime University

Effect of Voltage Fluctuations on Induction Motor Currents

2024-12-18T08:00:53+00:00

One of the types of power quality disturbances met in a power system is voltage fluctuations. Cyclic voltage fluctuations are interconnected with the presence of subharmonics and interharmonics – that is components of frequency less than the fundamental frequency or not being its integer multiple. Voltage fluctuations can be considered as practical examples of the simultaneous presence of subharmonics and interharmonics of various frequencies. This study deals with the preliminary investigations on an induction motor under voltage fluctuations of frequency greater than the supply voltage frequency. The results of the empirical investigations on currents under rectangular modulation of voltage amplitude are presented for a four-pole cage induction motor of a rated power of 4 kW.

Effect of Mains Communication Voltage on Induction Motors

2024-12-18T08:15:56+00:00

Power system lines are not only used for electric energy transfer, but also for the transmission of a communication signal, called the mains communication voltage. The mains communication voltage is in the form of a telegram code, superimposed on the fundamental voltage harmonic. From the point of view of power quality, mains communication voltage should be considered as interharmonics – components of frequency being not equal to the integer multiple of the fundamental frequency. Interharmonics have a negative impact on various energy receivers, including rotating machinery. This study is devoted to the effect of the mains communication voltage on an induction motor. The results of numerical computations on currents and electromagnetic torque pulsations are presented for a four-pole cage induction motor of rated power 3 kW.

Application of the Vivaldi Antenna in a Linear Antenna Array for Radar Systems

2024-06-19T11:50:40+00:00

The article presents a new broadband TSA antenna with a widening aperture, which is to be the basic radiating element in a multi-element antenna. The TSA antenna is characterized by a low-value standing wave ratio (SWR) covering the widest possible frequency band while maintaining a symmetrical and directional radiation pattern. The design was created using the WIPL-D computer program. This program enabled a computer simulation and the selection of the final solution. The "output" model is a radiator powered by a half-wave dipole. The results include the computer simulations of multi-element antennas, as well as the physical measurements carried out in an anechoic chamber for various configurations of antenna arrays. The discussion includes a number of significant problems that arise in the construction of antenna arrays, their various solutions, while the method of their power supply, as carried out in this paper, requires obtaining a bandwidth of 700–800 kHz for the SWR < 2 criterion (for radar applications this criterion is the more stringent SWR < 1, 3).

Effect of Temperature and Printing Angle in FDM Additive Printing on the Strength Properties of PET-G

2024-12-18T09:16:50+00:00

3D printing, also known as additive printing or additive manufacturing, has become an integral part of today’s manufacturing technologies, enabling rapid and flexible fabrication of three-dimensional objects from a variety of materials. Its importance in many fields is steadily increasing due its capabilities in prototyping, custom manufacturing and product personalisation. With the development of 3D printing technology, it is increasingly being used in the manufacture of marine machine parts and equipment. Before such products are implemented for real-world use, they require a thorough analysis of strength properties. In this work, the strength properties of the PET-G material were analysed with a change in temperature and printing angle using FDM (fused deposition modelling). Preliminary analysis of the results identified the best printing angle setting and the optimum choice of printing temperature.

Analyzing the Implementation Process for the Kaizen Method Based on the Example of ZSP „Lubiana” S.A.

2024-12-18T09:46:25+00:00

This covers a complex analysis of implementing the Kaizen method at ZPS „LUBIANA” S.A., a Polish company, in the years 2018-2022. This includes a brief assessment of the actions taken as an aftermath of wider practices aimed at perfecting the production process in the company through implementing organizational tools and practices related to the Lean Management concept.

The Kaizen method is related to the constant improvement of actions taken in a company, implemented as part of the Lean Manufacturing method, and used to improve production, minimize waste, maximize profit, increase employee engagement and product quality. The process of implementing the Kaizen method includes three stages: Identifying the issue, finding the solution and using a countermeasure, with an emphasis on small changes implemented by groups or quality circles.