Copper Loss Reduction Research Articles

Winding Design and Fabrication of a Miniature Axial-Flux Motor by Micro-Electroforming

In downsizing motor drives to fit in increasingly compact electronic products, the winding is the most awkward part to be scaled down from conventional motor design. The micro-electroforming process, however, can form products between micro and millimeter scale and is appropriate for manufacturing special winding conductor profiles. We describe a design for a miniature axial-flux motor based on a micro-electroformed winding. The design uses rhomboidal windings to reduce copper loss. We have verified the design by finite-element analysis, and we fabricated and inspected a prototype to demonstrate the effectiveness of the micro-electroforming procedure.

Reduction of Proximity Effect in Coil Using Magnetoplated Wire

The upgrading of the efficiency of transformers and increase in the quality factor of inductors are required. For this purpose, it is necessary to reduce copper loss. Reducing the winding AC resistance is one method of reducing copper loss. Therefore, we propose the use of magnetoplated wire (MPW) for coil windings. An MPW is a copper wire (Cu wire) whose circumference is plated with a magnetic thin film. The resistances due to the proximity effect of Cu wire and MPW coils at a frequency of f=1 MHz, which have a diameter of D=4.54 mm, a wire diameter of d=0.09 mm, and a number of turns of N=102, are 4.2 Omega and 2.1 Omega, respectively; thus, the proximity effect decreases by half

Transformers of reduced losses and evaluation of their repair

The purpose of this work is to determine the optimum reduction of iron and copper losses in distribution transformers. Design and life-cost calculations for transformers 20 kV/400 V of a nominal power 50–1000 kVA were performed, for estimating the final transformer price for different amounts of loss reduction, in order to find out the minimum annual operational cost of these transformers. For estimating the annual cost, the final transformer price and the power and energy cost due to the transformer losses have been used. In this way, the optimal losses (iron + copper) have been found out for the minimum annual cost. The impact of a damaged tranformer's age on the economic decision for its repair has been investigated as well.

Copper loss reduction of a voice-coil motor for cutting tool positioning using an auxiliary rotary motor

When a voice-coil motor is used for cutting tool positioning under load forces, it is likely to have a high copper loss and, consequently, a high temperature rise. A novel solution that uses an auxiliary rotary motor is proposed. The design approach is discussed. A design example with simulations is given.

OPTIMAL COMPENSATION OF NONUNIFORMLY LOADED RADIAL FEEDERS, WITH APPLICATIONS

ABSTRACT This paper presents a generalized mathematical model for assessing the loss reduction in nonunlformly loaded radial feeders by capacitor shunt compensation. The model allows for the simultaneous presence of linearly increasing feeder load density in addition to a concentrated load at the feeder end. Any number of compensating capacitors can be included in the analysis. The model is then applied to study the effect of the number of feeders on the achieveable optimal reduction in the feeder copper loss. The paper also gives the optimal size and locations of these capacitors, for any number of radial feeders eraenatlng from a distribution substation to serve a certain total load.

Optimal Efficiency Speed Control of Induction Motors by Variable Rotor Impedance

An optimal method to control the speed of a wound-rotor induction motor by variable external rotor impedance is presented. The rotor impedance is adjusted so that, for any desired torque and slip values, the total copper losses are minimized. Motor efficiency is improved compared with the case of conventional speed control by variable rotor resistance only. An example illustrates the copper loss reduction and dynamic behavior of the drive. Simulation study results that show the percentage copper loss reduction is generally likely to be higher for lighter loads. For constant-torque loads, the reduction percentage reaches a peak at the lower slip values, whereas for fan-type loads the most significant percentage copper-loss reduction occurs at both the higher and lower slip values. The response time of the rotor speed for startup or a sudden change in the speed setting is considerably smaller than that achieved by pure rotor resistance control. >

A study on the reduction of harmonic rotor copper losses of three‐phase squirrel cage induction motor driven by inverter

A study on the reduction of harmonic rotor copper losses of three‐phase squirrel cage induction motor driven by inverter

Eroberung des Festlands: Das Kupferproblem vom Gesichtspunkt der Isopoden

1. Copper is an element of great importance for crustaceans such as isopods and amphipods. While their marine relatives can obtain all necessary chemical components from the surrounding sea water via gills or other epithelia, the species which have conquered terra firma face the problem of extracting practically all vital substances from their food. 2. In marine forms, the water flow maintained via ciliary or muscular mechanisms is sufficient to provide several orders of magnitude more copper than required; food probably plays only a minor role in copper supply. 3. Terrestrial isopods have to rely entirely on their food as a source of copper. They can do several things in order to ensure an adequate supply: increase food consumption, improve the selective absorption of copper from the food material passing through the gut (possibly in symbiosis with copper concentrating micro-organisms), increase copper stores, thus widening safety margins for times of low supply, reduce copper losses by regulating the transport of this metal between the stores and other body parts. 4. It was shown that terrestrial isopods consume about as much food as their marine relatives. 5. Extraction of copper from primary vegetable matter seems to be very difficult, both for terrestrial forms likePorcellio scaber and for intertidal forms such asLigia oceanica or the amphipodOrchestia gammarella; extraction is possible only at very high copper concentrations. 6. A way out of this calamitous situation seems to be in cooperation with micro-organisms which liberate copper from the tightly bound states in which it exists in the primary plant material. This is true forP. scaber but it probably also holds forO. gammerella, L. oceanica and other species feeding on decaying algae on the shore. 7. The amount of copper stored in the hepatopancreas increases with increasing dependence of the species on the terrestrial environment, the values obtained for intertidal species being intermediate between marine and truly terrestrial species. 8.P. scaber (and probablyOniscus asellus) will extract up to 95% of the copper present in artificially enriched leaf litter whereas intertidal forms feeding onFucus will not extract more than 50%, mostly only 20% or less, from artificially enriched seaweeds. 9. Copper is more strictly relegated to “storage cells” of the hepatopancreas in terrestrial isopods than it is in marine or intertidal ones. Extensive movements of copper inP. scaber are accompanied by the synthesis of special “carrier proteins”, whereas in marine or intertidal species this metal seems to be able to move more freely in an easily dissociable state between the storage cells and other cells of the hepatopancreas.

Reduction of armature copper losses: The inverted turn transposition for the reduction of losses due to non-uniform current distribution in the armature conductors of large A-C. machines

A new method of reduction of armature copper losses is described, which consists in the inversion of the conductors of a multi-turn barrel type coil at one or more places in the end portions of the coil. Previous writers have described methods of transposing the conductors in the slot and of carrying insulated strands through successive positions in successive coils, but the new method now described presents distinct points of difference in theory and in construction from any of these earlier methods. The theory of the new form of transposition is briefly described, complete formulas are presented for the most useful cases, and illustrations of its use are given.

Reduction of armature copper losses

Reduction of armature copper losses

Reduction of Armature Copper Losses The Inverted Turn Transposition for the Reduction of Losses Due to Non-uniform Current Distribution in the Armature Conductors of Large A-C. Machines

A new method of reduction of armature copper losses is described, which consists in the inversion of the conductors of a multi-turn barrel type coil at one or more places in the end portions of the coil. Previous writers have described methods of transposing the conductors in the slot and of carrying insulated strands through successive positions in successive coils, but the new method now described presents distinct points of difference in theory and in construction from any of these earlier methods. The theory of the new form of transposition is briefly described, complete formulas are presented for the most useful cases, and illustrations of its use are given.