Ultra-Efficient and Power Dense Electric Motors for U. S. Industry

The primary purpose of this project was to combine the ease-of-installation and ease-of-use attributes of industrial induction motors with the low-loss and small size and weight advantages of PM motors to create an ultra-efficient, high power density industrial motor that can be started across-the-line or operated from a standard, Volts/Hertz drive without the need for a rotor position feedback device. PM motor products that are currently available are largely variable speed motors that require a special adjustable speed drive with rotor position feedback. The reduced size and weight helps to offset the magnet cost in order make these motors commercially viable. The scope of this project covers horsepower ratings from 20 ? 500. Prototypes were built and tested at ratings ranging from 30 to 250 HP. Since fans, pumps and compressors make up a large portion of industrial motor applications, the motor characteristics are tailored to those applications. Also, since there is extensive use of adjustable frequency inverters in these applications, there is the opportunity to design for an optimal pole number and operate at other than 60 Hz frequency when inverters are utilized. Designs with four and eight pole configurations were prototyped as part of this work. Four pole motors are the most commonly used configuration in induction motors today. The results of the prototype design, fabrication, and testing were quite successful. The 50 HP rating met all of the design goals including efficiency and power density. Tested values of motor losses at 50 HP were 30% lower than energy efficient induction motors and the motor weight is 35% lower than the energy efficient induction motor of the same rating. Further, when tested at the 30 HP rating that is normally built in this 286T frame size, the efficiency far exceeds the project design goals with 30 HP efficiency levels indicating a 55% reduction in loss compared to energy efficient motors with a motor weight that is a few percentage points lower than the energy efficient motor. This 30 HP rating full load efficiency corresponds to a 46% reduction in loss compared to a 30 HP NEMA Premium? efficient motor. The cost goals were to provide a two year or shorter efficiency-based payback of a price premium associated with the magnet cost in these motors. That goal is based on 24/7 operation with a cost of electricity of 10 cents per kW-hr. Similarly, the 250 HP prototype efficiency testing was quite successful. In this case, the efficiency was maximized with a slightly less aggressive reduction in active material. The measured full load efficiency of 97.6% represents in excess of a 50% loss reduction compared to the equivalent NEMA Premium Efficiency induction motor. The active material weight reduction was a respectable 14.5% figure. This larger rating demonstrated both the scalability of this technology and also the ability to flexibly trade off power density and efficiency. In terms of starting performance, the 30 ? 50 HP prototypes were very extensively tested. The demonstrated capability included the ability to successfully start a load with an inertia of 25 times the motor?s own inertia while accelerating against a load torque following a fan profile at the motor?s full nameplate power rating. This capability will provide very wide applicability of this motor technology. The 250 HP prototype was also tested for starting characteristics, though without a coupled inertia and load torque. As a result it was not definitively proven that the same 25 times the motor?s own inertia could be started and synchronized successfully at 250 HP. Finite element modeling implies that this load could be successfully started, but it has not yet been confirmed by a test

The effect of behind-the-scenes encounters and interactive presentations on the welfare of captive servals (Leptailurus serval)

The serval (Leptailurus serval) is a small African felid that is well represented in zoos and often serves as an animal ambassador in encounter programs with zoo visitors. The impact on serval welfare in relation to such programs has not been investigated to date, and the aim of this study was to assess short-term welfare effects of varying levels of visitor interaction in two captive servals. Weekly blocks of four different treatments were imposed three times on each animal over 12 weeks, and the treatments involved (1) Presentations (serval undertaking a routine training session in a designated presentation space, typically attracting high visitor numbers), (2) Behind-the-scenes (BTS, a close encounter allowing a small group of visitors to interact closely with the cat in its enclosure), (3) Presentations and BTS combined, and (4) No visitor interaction. Serval activity budgets as well as behavioural diversity were created from behaviours observed from Close Circuit Television (CCTV) footage during four daily recording sessions per animal over three consecutive days per treatment, using instantaneous scan sampling every 60 s. Individual faecal samples were collected daily to monitor changes in faecal glucocorticoid metabolite (FGM) concentration. Results indicate that the mean number of scans with stereotypic pacing was significantly reduced (p = 0.01) during Treatments 1 and 3, when cats participated in presentations only, or the two activities combined. Conversely, a significant reduction in behavioural diversity (p 0.05). Given the reduction in stereotypic pacing, these findings suggest that involvement in an encounter program appears to exert an overall positive short-term welfare effect on the individual servals in this study. Although a reduction in behavioural diversity was not considered a negative welfare effect in the short term, potential long-term negative welfare effects resulting from a more frequent encounter program could not be ruled out in the present study

A comprehensive overview of radioguided surgery using gamma detection probe technology

The concept of radioguided surgery, which was first developed some 60 years ago, involves the use of a radiation detection probe system for the intraoperative detection of radionuclides. The use of gamma detection probe technology in radioguided surgery has tremendously expanded and has evolved into what is now considered an established discipline within the practice of surgery, revolutionizing the surgical management of many malignancies, including breast cancer, melanoma, and colorectal cancer, as well as the surgical management of parathyroid disease. The impact of radioguided surgery on the surgical management of cancer patients includes providing vital and real-time information to the surgeon regarding the location and extent of disease, as well as regarding the assessment of surgical resection margins. Additionally, it has allowed the surgeon to minimize the surgical invasiveness of many diagnostic and therapeutic procedures, while still maintaining maximum benefit to the cancer patient. In the current review, we have attempted to comprehensively evaluate the history, technical aspects, and clinical applications of radioguided surgery using gamma detection probe technology

Ultra-Efficient and Power Dense Electric Motors for U. S. Industry

The primary purpose of this project was to combine the ease-of-installation and ease-of-use attributes of industrial induction motors with the low-loss and small size and weight advantages of PM motors to create an ultra-efficient, high power density industrial motor that can be started across-the-line or operated from a standard, Volts/Hertz drive without the need for a rotor position feedback device. PM motor products that are currently available are largely variable speed motors that require a special adjustable speed drive with rotor position feedback. The reduced size and weight helps to offset the magnet cost in order make these motors commercially viable. The scope of this project covers horsepower ratings from 20 ? 500. Prototypes were built and tested at ratings ranging from 30 to 250 HP. Since fans, pumps and compressors make up a large portion of industrial motor applications, the motor characteristics are tailored to those applications. Also, since there is extensive use of adjustable frequency inverters in these applications, there is the opportunity to design for an optimal pole number and operate at other than 60 Hz frequency when inverters are utilized. Designs with four and eight pole configurations were prototyped as part of this work. Four pole motors are the most commonly used configuration in induction motors today. The results of the prototype design, fabrication, and testing were quite successful. The 50 HP rating met all of the design goals including efficiency and power density. Tested values of motor losses at 50 HP were 30% lower than energy efficient induction motors and the motor weight is 35% lower than the energy efficient induction motor of the same rating. Further, when tested at the 30 HP rating that is normally built in this 286T frame size, the efficiency far exceeds the project design goals with 30 HP efficiency levels indicating a 55% reduction in loss compared to energy efficient motors with a motor weight that is a few percentage points lower than the energy efficient motor. This 30 HP rating full load efficiency corresponds to a 46% reduction in loss compared to a 30 HP NEMA Premium? efficient motor. The cost goals were to provide a two year or shorter efficiency-based payback of a price premium associated with the magnet cost in these motors. That goal is based on 24/7 operation with a cost of electricity of 10 cents per kW-hr. Similarly, the 250 HP prototype efficiency testing was quite successful. In this case, the efficiency was maximized with a slightly less aggressive reduction in active material. The measured full load efficiency of 97.6% represents in excess of a 50% loss reduction compared to the equivalent NEMA Premium Efficiency induction motor. The active material weight reduction was a respectable 14.5% figure. This larger rating demonstrated both the scalability of this technology and also the ability to flexibly trade off power density and efficiency. In terms of starting performance, the 30 ? 50 HP prototypes were very extensively tested. The demonstrated capability included the ability to successfully start a load with an inertia of 25 times the motor?s own inertia while accelerating against a load torque following a fan profile at the motor?s full nameplate power rating. This capability will provide very wide applicability of this motor technology. The 250 HP prototype was also tested for starting characteristics, though without a coupled inertia and load torque. As a result it was not definitively proven that the same 25 times the motor?s own inertia could be started and synchronized successfully at 250 HP. Finite element modeling implies that this load could be successfully started, but it has not yet been confirmed by a test

Ensuring tests of conservation interventions build on existing literature.

No abstract available