In the late 19th century, the three-phase induction motor was the central element of productivity increase in the second industrial revolution in Europe and the United States. Currently, it is the main load on electrical systems in global terms, reaching approximately 70% of electrical energy consumption in the industrial sector worldwide. During the 20th century, electric motors underwent intense technological innovations that enabled significant performance gains. Thus, this work analyses the performance changes in squirrel-cage rotor three-phase induction electric motors (SCIMs) with mechanical powers of 3.7 kW, 37 kW, and 150 kW and speed ranges corresponding to two poles and eight poles, connected to a low voltage at a frequency of 60 Hz and tested between 1945 and 2020. The study confirms accumulated performance gains of above 10% in some cases. Insulating materials for electrical conductors have gone through several generations (cotton, silk, and currently, varnish). Improvements to the housing for cooling, the bearings, the quality of active materials, and the design were the elements that enabled the high gains in performance. The first commercial two-pole SCIM with a shaft power of 4.4 kW was marketed in 1891, with a weight/power ratio of 86 kg/kW, and until the 2000s, this value gradually decreased, eventually reaching 4.8 kg/kW. Between 2000 and 2020, this ratio showed a reversed trend based on improvements in the performance of SCIMs. More active materials were used, causing the weight/power ratio to reach 8.6 kg/kW. The MEPS (minimum energy performance standards) of SCIMs had an essential role in the performance gain over the last three decades. Data collection was via tests at the Electrical Machines Laboratory of the Institute of Energy and Environment of the University of São Paulo. The laboratory has a history of tests on electrical equipment dating from 1911.

With the current concerns about sustainable development and energy consumption in buildings, water pumping systems have become essential for reducing energy consumption. This research aims to develop guidelines for the energy assessment of water pumping systems in multifamily buildings. The methodological procedures are: (i) definition of the efficiencies of electric motors; (ii) definition of pump efficiency levels; (iii) determination of energy consumption; and (iv) construction of the efficiency scale and guidelines for projects and assessments. The results obtained were that centrifugal pumps with 40% efficiency have higher energy consumption, regardless of the efficiency class of the electric motors, showing a 20% increase in electrical energy consumption. Lower efficiencies directly impact the energy efficiency rating of the water pumping system. Thus the 40% efficiency obtained energy efficiency rating “Very Low—VL” for all motor efficiency classes (between IE1 and IE5). At 60% efficiency, the energy efficiency level of the system was “Average—A”, gradually increasing to “Very High—VH”, as the energy consumption in the pumps decreased and the motors’ energy efficiency classes increased. It is concluded that designers and professionals in the area must consider the efficiency of the pumps, as they play a fundamental role in the classification of the system’s energy efficiency. It is also recommended to verify the energy efficiency of the water pumping system and implement design guidelines so that the pumping system achieves lower energy consumption, contributing to the building’s energy efficiency and sustainability.

Accidents caused by electricity are responsible for countless deaths and injury to people/animals and damage to buildings and facilities worldwide. Although sufficient knowledge is available on making electrical installations safe, many countries do not have organized data on accidents of electrical origin, making it challenging to implement effective public policies to reduce the risk. Therefore, this research aims to present a methodology for collecting data on electrical accidents, involving electric shock, through the Google LLC Alert monitor and analyzing it. The application of this approach in Brazil between 2013 and 2021 validates this methodology. The analysis shows that accidents leading to fatal shock between 2013 and 2021 increased by 44%, and more than 95% of the victims were men. In total 2,680 cases were analyzed, including detailed information about age, sex, the location of the accident, date, and main cause. Consequently, preventive guidelines for the principal types of accidents can be developed.

Two main features provided by electric motor manufacturers are power factor and efficiency. However, the values reported are often different from the measured values. Thus, this work presents the results obtained from testing 435 Three-phase Induction Electric Motors with Squirrel Cage Rotor from 38 different manufacturers tested between 2015 and 2016. The data were collected through standardized tests performed at the Laboratory of Electrical Machines of the Institute of Energy and Environment of the University of Sao Paulo. The values reported by the manufacturers were compared with the values measured in the laboratory. The results indicate that 58% of the values measured for the power factor of the motors were lower than those reported by the manufacturer. Similarly, 55% of the measured values for the performance were lower than the values reported by the manufacturer.

An evaluation of relevance of Current Asymmetry on Arc Flash tests intended to determine Arc rating parameters on fabrics and garments, as well as face shields, gloves and other materials was performed. Asymmetrical current is mentioned in American Standards (ASTM F 1959) to be maximum during tests and a reference on International Standard IEC 61482-1-1:2009, item 6.9, where an X/R ratio is required to obtain an asymmetry factor of 2.3, with a recommended source voltage of 2000 V. IEEE 1584 studies on the other hand states all calculation processes not clearly regarding asymmetry of fault current but assuming the linear effect of time and current on energy derived from steady state current values. Technical basement for the asymmetry factor is never mentioned on arc flash test standards but it is supposed to be related to test strength conditions. As thermal conversion relationship with asymmetry is not clear in the literature the present study investigated, simulated and performed practical measurements of electrical and thermal parameters related to Arc Flash tests, concluding that both symmetrical and asymmetrical arcing currents will confer the same arc rating results. Practical tests also showed that a source voltage of 2000 V is necessary only to produce arcing current asymmetry as lower voltages can be used to ignite and keep symmetrical arcing current for sufficient time on the arc rating tests, as previously regarded on literature which reduces significantly test setup and circuitry.