Control Gear Research Articles

Comment 1 on ‘Advantages and disadvantages of the use of compact fluorescent lamps with electronic control gear’ by FV Topalis, MB Kostic and ZR Radakovic

Comment 1 on ‘Advantages and disadvantages of the use of compact fluorescent lamps with electronic control gear’ by FV Topalis, MB Kostic and ZR Radakovic

Comment 2 on ‘Advantages and disadvantages of the use of compact fluorescent lamps with electronic control gear’ by FV Topalis, MB Kostic and ZR Radakovic

Comment 2 on ‘Advantages and disadvantages of the use of compact fluorescent lamps with electronic control gear’ by FV Topalis, MB Kostic and ZR Radakovic

Advantages and disadvantages of the use of compact fluorescent lamps with electronic control gear

The paper presents a comprehensive analysis dealing with the behaviour and economics of electronic compact fluorescent lamps. The economic analysis, based on the results of the test concerning the lifetime and the lamp lumen maintenance factor of electronic compact fluorescent lamps, and conducted using the cost-discount method, showed an obvious advantage for lamps of this type compared with incandescent ones. The strategic importance of the mass use of electronic compact fluorescent lamps, as well as serious power quality implications it can cause to the network, are explained in detail. Possible solutions of this problem are also presented.

An attempt to improve size selection in pelagic longline fisheries for haddock

Bycatches of haddock ( Melanogrammus aeglefinus) below legal size (44 cm total length) in the pelagic longline fisheries off the coast of Finnmark, northern Norway, are often high. To reduce the bycatch of undersized haddock, we conducted experiments involving modifications in gear technology and fishing strategy. We tested longlines with a greater rate of sinking, hooks with an inedible plastic body attached to the shank, hooks with nylon bristles attached to the shank, restructured bait based on mackerel ( Scomber scombrus) and sandeel ( Ammodytes lancea), mackerel bait of twice the normal size and restructured mackerel bait of twice the normal size. The inedible plastic body reduced the catch of undersized haddock, as well as the total catch. Restructured sandeel bait gave a significant decrease in catches of undersized haddock, but the number of hooks deployed in this part of the experiment was small. Traditional mackerel bait of twice the normal size resulted in about a 40% reduction in the catch of undersized fish. Catch proportions between length groups in the alternative gears compared to control gear or length distribution based on acoustical data indicate a unimodal selection curve for the alternative gears.

Size selectivity of trap for male red queen crab Chionoecetes japonicus with the extended SELECT model

SUMMARY: A series of comparative fishing experiments was carried out in waters off the east coast of Korea in 1997, using traps of six different mesh sizes (95, 112, 122, 132, 152, and 172 mm mesh opening) to determine the size selectivity of a conical trap for male red queen crab, Chionoecetes japonicus. The extended SELECT (Share Each LEngth’s Catch Total) analysis method was applied with fishing effort data to obtain trap size selectivity, with a symmetric logistic equation used to express selectivity curves. Traps of 95 mm mesh size were employed as the control gear in the analysis. Logistic and split parameters of each mesh-size trap in the SELECT model were calculated by the maximum likelihood method. The model of split parameter p fixed with equal fishing efficiency, was chosen from the likelihood ratio tests and Akaike’s Information Criterion (AIC) comparison. From the determined logistic parameters, the carapace widths of 50% retention were estimated to be 82, 85, 92, and 101 mm for 122, 132, 152, and 172 mm mesh-size traps, respectively. The selectivity curves of each mesh-size trap showed that traps of larger mesh size allowed more crabs of small carapace width and low commercial value to escape.

Achieving IEC Type 2 short circuit coordination

It is becoming general knowledge that simply meeting UL requirements and installing equipment per the National Electrical Code does not necessarily prevent severe component damage in the event of a short circuit. Motor control and fuse manufacturers have introduced a new term to the North American market that describes the level of short circuit protection provided to the motor starter in a motor branch circuit. That new term is Type 2 Coordination. This paper explains the test and pass/fail criteria to meet the new Type 2 coordination requirements of IEC 947-4-1. Methods of meeting these requirements and a major test program involving both NEMA and IEC control gear is addressed in detail.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Integral equation approach for the analysis of three-dimensional transient electromagnetic heating effects

An integral approach for the analysis of three-dimensional transient electromagnetic heating effects is presented. The conductor bodies are decomposed in elementary parallelepipeds, and the centers of nearby parallelepipeds are connected in order to obtain a three-dimensional grid. The electrical and thermal equilibrium equations applied to this grid allow the evaluation of the current density and the temperature distribution inside the conductors of the system. The characteristics of the approach are shown through simulations of the tests provided in the experimental verifications of switchgear and control gear assemblies. >

Lighting control: Feasibility demonstration of a new type of system

A new lighting control system was developed to improve the effective use of electrical energy, building space, and human effort. The prototype control system described in this report (ImCon) consists of a small charge-coupled device (CCD) camera, a personal computer, and peripheral lighting control gear. The computer is programmed with rules to adjust the lighting conditions to meet the demands imposed by multiple occupants and visual tasks in a single room while minimising wasted lighting energy. The purpose of this paper is to introduce the patented ImCon system and the philosophy behind it. Subsequent publications will contain performance data from a real space presently under construction.

点灯装置の技術動向と展望

点灯装置の技術動向と展望

Implementation of Microcomputers in the Control of Direct Gain Passive Solar Systems

The present paper investigates the problem of designing control gear for direct gain system applications. First the direct gain systems are briefly reviewed and the controller requirements are established. Next the decision to apply ON/OFF control strategy is made. Then a controller design based on a single chip computer (68701) is described including the choice and necessary interface of the temperature and humidity sensors.

Low Pressure Sodium Lamps with a Luminous Efficacy of 200 lm/W

The characteristics of the new range of energy SOX-E lamps are presented. The SOX-E 131 lamp has an efficacy of 200 lm/W. Its performance on existing, as well as on new more efficient control gear is described.

A new pole-changing winding using star/star-delta switching

A new pole-changing winding using star/star-delta switching is developed and is shown suitable for wide pole-ratio single-winding induction motors with pole combinations of the form (i) even/even and (ii) odd/odd pole pairs. Examples of 1:5 and 5:1 pole ratios are presented. Test results on laboratory-size machines for these pole ratios confirm the usefulness of the proposed schemes. The proposed arrangements are found to be superior to earlier designs in respect of either MMF/harmonic content or frame utilisation at both the pole settings. Change of speed is obtained using only six terminals and a control gear which is even simpler than the one used for any other pole-changing 3-phase winding.

Marketing of electrical products

Many electrical engineers have little detailed knowledge of the duties and functions of sales and marketing departments. The paper, based on the author&apos;s 25 years of experience of selling, marketing and managing in the electrical power and control industry, analyses the subject under the headings of market research and executive marketing, explaining in detail the tasks performed in communicating the requirements of the market to the producer and also in communicating details of the product to the market. While practical examples of marketing and selling are given in relation to the motor control gear and other electrical component manufacturing industries, their relevance can be appreciated by engineers in systems manufacturing, service and user industries, whether electronic or power based. The last Section of the paper deals with selling and sales management and aims to clarify the distinction between sales and marketing.

An Erosion-Resistant Lithium Additive Modified Ag-CdO

A new modified heterogeneous alloy composition is presented that has been proved to reduce the consumption of silver per operation in 600 VAC motor control gear. The new modified alloy is a powder-metallurgical heterogeneous type of Ag-CdO that preserves ali the typical properties found in conventional powder-metallurgical Ag-CdO. However, the new modified alloy has shown erosion rates in electrical endurance testing that are one-half that expected from conventional Ag-CdO. The new alloy is a lithium-modified Ag-CdO. The lithium content must be controlled in the range of 40-60 parts per million (ppm) by weight to achieve optimum electrical endurance with this contact material. Data derived from IEC, AC-3 tests for motor control gear are presented to support the above electrical endurance claims. A theoretical discussion of the mechanism of erosion reduction produced with this alloy is included.

The Motor Control Switching Performance of Cu-CdO Contacts in a Helium Atmosphere

An investigation of the arc rupture capacity and electrical endurance of Cu-l0 weight percent CdO and Ag-l0 weight percent CdO in motor control gear. In addition, the arc rupture capacity and electrical endurance of Cu-l0 weight percent CdO in helium at 1 atm is presented. Cu-CdO contacts in a helium atmosphere are observed to perform motor control switching duty with similar electrical performance to that registered by Ag-CdO contacts operated in air. The theoretical aspects of the electrical switching of typical motor control loads in contained environments, such as helium, and the possible applications of this type of switch are discussed.

How to Control Gear Noise and Vibrations

How to Control Gear Noise and Vibrations

Quality and performance of discharge lamp control gear

The criteria by which control gear is judged are discussed. The reasons why there are differences between units, and the methods of measuring these differences, are described. It is shown how this quality assurance effort is directed towards factory production control.

The Influence of Thyristor Control on Traction Motors

Publisher Summary Traction duty efforts free choice of speed and acceleration of a vehicle within certain limits. Allowing for gear and wheel-diameter, the tractive effort of the vehicle responds to the motor-torque and vehicle speed to motor speed. The magnetic flux is—on account of the right angle between the axes of the windings of armature and excitation—without influence by the armature circuit excited by the excitating current only. On account of this simple possibility of speed control, the commutator motor has conquered the field of electrical traction. The motor is series-wound and controlled by means of series resistances and multiple series. Field weakening by means of shunts is possible as well. The mechanic elements like on-load tap changers of the transformer or control gears become unnecessary, there are no losses in resistors, travelling becomes more comfortable on account of the continuous control, the control works extremely fast in case of a disturbance.

The impact of electronics on lighting

In recent years electronics has had an impact on almost every aspect of lamps and lighting from escape lighting to son et lumière, from reduction of gear losses to reduction of flicker, from tunnel lighting to theatre lighting, from automobile lighting to automation of lamp making machinery. Electronics is helping safety with hazard warning lights, automatically compensated tunnel lighting and measuring equipment to correlate street lighting with road accidents. The use of electronic ignitors to start high intensity discharge lamps assists energy conservation and reduces the material content of the control gear while invertor operated fluorescent tubes for transport lighting has to meet stringent requirements on transients.

Semiconductor ballast circuits for discharge lamps

Semiconductor circuits used in place of conventional control gear can reduce the size and weight of discharge lamp ballasts, and in many cases improve both lamp and overall efficiencies. The paper describes small semiconductor — series choke arrangements which could replace large leakage transformers or choke—transformer combinations. A number of different practical semiconductor ballast circuits with thyristors and transistors are discussed. Some design problems and the effects on discharge lamp performance are also mentioned.