scholarly journals Kinematical characteristic of mechanical frictional variable speed drive

2012 ◽  
Vol 52 (No. 2) ◽  
pp. 61-68
Author(s):  
D. Herák ◽  
V. Šleger ◽  
R. Chotěborský ◽  
K. Houška ◽  
E. Janča
Keyword(s):  
Power Transmission ◽  
Transmission Efficiency ◽  
Variable Speed ◽  
Variable Speed Drives ◽  
The Real ◽  
Theoretical Design ◽  
Conversion Unit ◽  
Real Characteristic ◽  
Low Efficiency ◽  
Ring Position

The paper describes a new system of mechanical spherical conical friction drive. In the present a row of simple friction, belt, chain, wave and differential variable speed drives is published. For the required range of speed variation they are altogether unfit. The currently used power transmissions are of low efficiency (60–70%). Therefore the better power transmission efficiency is required. The possibility of multicontact power transmission appears as the most suitable principle of the power transmission. Using the designed function model, which was made according to the small tractor producers requirements, the real output kinematical characteristic was measured. It is derived the complete drive conversion unit kinematics and the theoretical kinematical characteristic design. The theoretical design is compared with the real characteristic determined by measuring using the test station. From the measured values we determined that the geometrical characteristic, i.e. the relation between output speed and ring position, corresponds in the ring position range (2.8÷14) mm to the theoretical premise.

Improving the efficiency of oilfield electric power distribution

2019 ◽  
pp. 79-87
Author(s):  
Yu. F. Yu. F. Romaniuk ◽  
О. V. Solomchak ◽  
М. V. Hlozhyk
Keyword(s):  
Power Distribution ◽  
Reactive Power ◽  
Power Transmission ◽  
Transmission Efficiency ◽  
Active Power ◽  
Oil Field ◽  
Total Power ◽  
Simultaneous Increase ◽  
Active Load ◽  
Step Down

The issues of increasing the efficiency of electricity transmission to consumers with different nature of their load are considered. The dependence of the efficiency of the electric network of the oil field, consisting of a power line and a step-down transformer, on the total load power at various ratios between the active and reactive components of the power is analyzed, and the conditions under which the maximum transmission efficiency can be ensured are determined. It is shown by examples that the power transmission efficiency depends not only on the active load, but also largely on its reactive load. In the presence of a constant reactive load and an increase in active load, the total power increases and the power transmission efficiency decreases. In the low-load mode, the schedule for changing the power transmission efficiency approaches a parabolic form, since the influence of the active load on the amount of active power loss decreases, and their value will mainly depend on reactive load, which remains unchanged. The efficiency reaches its maximum value provided that the active and reactive components of the power are equal. In the case of a different ratio between them, the efficiency decreases. With a simultaneous increase in active and reactive loads and a constant value of the power factor, the power transmission efficiency is significantly reduced due to an increase in losses. With a constant active load and an increase in reactive load, efficiency of power transmission decreases, since with an increase in reactive load, losses of active power increase, while the active power remains unchanged. The second condition, under which the line efficiency will be maximum, is full compensation of reactive power.  Therefore, in order to increase the efficiency of power transmission, it is necessary to compensate for the reactive load, which can reduce the loss of electricity and the cost of its payment and improve the quality of electricity. Other methods are also proposed to increase the efficiency of power transmission by regulating the voltage level in the power center, reducing the equivalent resistance of the line wires, optimizing the loading of the transformers of the step-down substations and ensuring the economic modes of their operation.

Опыт использования частотных преобразователей на объектах ООО «Водоканал»

2020 ◽  
Author(s):  
Sergei, Rybel’ ◽  
V. Kuninin ◽  
S. Gerasimov ◽  
A. Bakushin
Keyword(s):  
Inrush Current ◽  
Electric Motors ◽  
Variable Speed ◽  
Variable Speed Drives ◽  
Technical Device ◽  
Advantages And Disadvantages ◽  
Subsequent Period ◽  
Pumping Stations ◽  
Current Water ◽  
Pumping Equipment

Приведен опыт применения частотно-регулируемых электроприводов на насосных станциях ООО Водоканал г. Новокузнецка. Приводятся преимущества и недостатки данного технического устройства. Показано, что в настоящее время использование частотно-регулируемых приводов позволило снизить потребление электроэнергии более чем на 20, уменьшить затраты на ремонт и обслуживание, повысить срок службы электродвигателей, уменьшить величину пускового тока, снизить утечки воды и нагрузку на насосное оборудование и трубопроводную арматуру. Применение частотно-регулируемых электроприводов оправдало себя и в тех случаях, когда требуется регулирование параметров для обеспечения технологии (регулирование скорости, производительности и т. д.), приведение параметров оборудования к требуемым значениям без его замены (в расчете на увеличение загрузки оборудования до номинала в последующий период), компенсация суточной неравномерности потребления воды.The experience of using variable speed drives at the pumping stations operated by Vodokanal LLC in Novokuznetsk is presented. The advantages and disadvantages of this technical device are specified. It is demonstrated that currently, the use of variable speed drives provides for reducing the energy consumption by more than 20, reducing the repair and maintenance costs for improving the service life of electric motors for reducing inrush current, water leaks and the load on the pumping equipment and pipeline valving. The use of variable speed drives has paid off even in case where adjusting the parameters to ensure the technology (velocity, performance, etc.) bringing the equipment parameters to the required values without replacing it (in order to increase the equipment load to the nominal value for the subsequent period) compensating for daily irregularities in water consumption are required.

Compensating Resonant Frequency via Adjusting Adjustable Coil Automatically

2019 ◽  
Vol 12 (5) ◽  
pp. 432-438
Author(s):  
Jin Xu ◽  
Yuting Zhao
Keyword(s):  
Resonant Frequency ◽  
Power Transmission ◽  
Reference Value ◽  
Transmission Efficiency ◽  
Theoretical Research ◽  
Future Research ◽  
Wireless Power ◽  
Wireless Power Transmission ◽  
Resonant Coupling ◽  
Transmission Distance

Background: Detuning is the main problem that affects the efficiency and transmission distance of the resonant coupling Wireless Power Transmission (WPT). The distance of load and the offset of the load position could cause serious detuning. Methods: This paper presents an adjustable coil in which inductance can be adjusted. Then a model of WPT was established that could compensate resonant frequency automatically using the adjustable coil. Next, the relationship between the primary resonant frequency and the transmission efficiency is analyzed from the circuit. The analysis proved that the design of the adjustable coil could improve the transmission efficiency of the WPT system. Finally, a prototype of WPT system was built. Results: The experimental results showed that WPT system with adjustable coil can improve the transmission efficiency which proves the theoretical research. At the same time, it has essential reference value for the future research of WPT. Conclusion: In this paper, aiming at the system detuning caused by some other factors, such as the position shift of the load during the wireless power transmission, an adjustable coil is proposed.

Adjustable frequency invertors and their application to variable-speed drives

1964 ◽  
Vol 10 (11) ◽  
pp. 389 ◽  
Author(s):  
D.A. Bradley ◽  
C.D. Clarke ◽  
R.M. Davis ◽  
D.A. Jones
Keyword(s):  
Variable Speed ◽  
Variable Speed Drives

scholarly journals Common-Mode Voltage Harmonic Reduction in Variable Speed Drives Applying a Variable-Angle Carrier Phase-Displacement PWM Method

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2929
Author(s):  
Abraham Marquez Alcaide ◽  
Vito Giuseppe Monopoli ◽  
Xuchen Wang ◽  
Jose I. Leon ◽  
Giampaolo Buticchi ◽  
...  
Keyword(s):  
Carrier Phase ◽  
Harmonic Distortion ◽  
Harmonic Spectrum ◽  
Hydraulic Systems ◽  
Variable Speed ◽  
Common Mode ◽  
Variable Speed Drives ◽  
Phase Displacement ◽  
Common Mode Voltage ◽  
External Component

Electric variable speed drives (VSD) have been replacing mechanic and hydraulic systems in many sectors of industry and transportation because of their better performance and reduced cost. However, the electric systems still face the issue of being considered less reliable than the mechanical ones. For this reason, researchers have been actively investigating effective ways to increase the reliability of such systems. This paper is focused on the analysis of the common-mode voltage (CMV) generated by the operation of the VSDs which directly affects to the lifetime and reliability of the complete system. The method is based on the mathematical description of the harmonic spectrum of the CMV depending on the PWM method implementation. A generalized PWM method where the carriers present a variable phase-displacement is developed. As a result of the presented analysis, the CMV reduction is achieved by applying the PWM method with optimal carrier phase-displacement angles without any external component and/or passive filtering technique. The optimal values of the carrier phase-displacement angles are obtained considering the minimization of the CMV total harmonic distortion. The resulting method is easily implementable on mostly off-the-shelf mid-range micro-controller control platforms. The strategy has been evaluated in a scaled-down experimental setup proving its good performance.

A novel cooling geometry for subsea variable speed drives

2021 ◽  
Vol 185 ◽  
pp. 116483
Author(s):  
Lucas A. Militão ◽  
Caio D. Fernandes ◽  
Diego dos Santos ◽  
Douglas M. Machado ◽  
Marcelo L. Heldwein ◽  
...  
Keyword(s):  
Variable Speed ◽  
Variable Speed Drives
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