Showing papers on "Variable-frequency drive published in 1994"
20 Jun 1994
TL;DR: In this article, the impact of the harmonic limits of IEEE Standard 519-1992 on the industrial power consumer and the differences between the 1992 and 1981 versions of the Standard are discussed.
Abstract: When large harmonic producing loads are added to an industrial plant power system it is good engineering practice to analyze their impact on the power system by performing harmonic modeling analysis of the system at the design stage. Such a study can identify any potentially harmful resonances or other harmonic levels that are predicted to be in excess of IEEE 519 recommended limits and suggest corrective measures (if necessary). This paper discusses the impact of the harmonic limits of IEEE Standard 519-1992 on the industrial power consumer and addresses the differences between the 1992 and 1981 versions of the Standard. Harmonics produced by variable frequency drives are discussed. The data required to conduct a harmonic study, the types of analyses that can be performed, and some of the mitigating measures that can be taken to alleviate a potential harmonic problem are detailed. A case study is presented based on a typical paper mill where a large variable frequency drive was added to the power system.
62 citations
Patent•
16 Nov 1994
TL;DR: In this paper, a fluid flow delivery system switches a variable speed pump drive among a plurality of pumps to provide relatively low levels of fluid output, in response to low demand, and can be operated in combination with one or more constant speed pumps.
Abstract: A fluid flow delivery system switches a variable speed pump drive among a plurality of pumps. The remaining pumps can be operated as constant speed pumps and can be energized one at a time in response to increasing demand. The pump associated with the variable speed drive can be operated over a variable output range to provide relatively low levels of fluid output, in response to low demand, and can be operated in combination with one or more constant speed pumps to provide increased levels of output fluid in response to greater demand levels.
57 citations
20 Jun 1994
TL;DR: In this article, a general methodology for computing voltage and current distortion in accordance with IEEE 519-1992 is presented, and the impact of the new standard on the state-of-the-art of VFD technology is discussed.
Abstract: The new revision of IEEE Standard 519 became official in 1993. The new standard has been greatly expanded and includes additional stringent limits on individual and total current harmonic distortion in addition to the voltage distortion and line notching limits already included in IEEE Standard 519-1981. A modern industrial power system may include variable frequency drive (VFD) loads at several locations. The new standard requires a careful "global" harmonic analysis of the entire power system to specify the right type of VFD technology for the application and ensures compliance with the standard. This paper presents a general methodology for computing voltage and current distortion in accordance with IEEE 519-1992. The paper presents a case study that further emphasizes the importance of harmonic analysis. The impact of the new standard on the state-of-the-art of VFD technology is discussed. >
14 citations
01 Sep 1994
TL;DR: In this article, a case of EMI from a digital climate-control system of a building housing a data-processing facility was considered. And integrated barrier, filter and ground techniques were used to reduce the conducted and radiated EMI to harmless levels.
Abstract: : In recent years a significant number of digital devices and systems have been added to receiving and data-processing sites. These additions have enhanced the ability of the sites to accomplish their mission. They have also introduced new kinds of electromagnetic interference (EMI) into these sites along with accompanying performance degradation problems. In this thesis one specific case of EMI is considered. It is EMI from a digital climate-control system of a building housing a data-processing facility. The digital system generated excessive amounts of EMI. The EMI was conducted throughout the site over power and control conductors. Electromagnetic fields from EMI current flowing in these conductors coupled the EMI into other nearby conductors. Integrated barrier, filter, and ground techniques were used to reduce the conducted and radiated EMI to harmless levels. Electromagnetic interference, Electromagnetic compatibility, Barriers filters, Grounds, Variable-Frequency drive controller, Variable speed motors, EMI standards.
1 citations
20 Jun 1994
TL;DR: A variable frequency drive with sinusoidal line side power converter was applied to a new 350hp induction motor driving a kiln at Mead Coated Board's Alabama paper mill in early 1994 as discussed by the authors.
Abstract: A variable frequency drive with sinusoidal line side power converter was applied to a new 350 hp induction motor driving a kiln at Mead Coated Board's Alabama paper mill in early 1994. The purpose of the installation was to replace an existing 250 hp motor and drive with a 350 hp unit. In addition with the GD4000 sinusoidal rectifier, the mill saw benefits in both line harmonic distortion and effects on system power factor. The results of this installation, including its effects on Mead's power system are described. >