Method For Direct Measurement Research Articles

GIS vibration test method and characteristic signal recognition

Based on the characteristics of GIS insulation and mechanical fault types and practical measurement experience, two typical vibration measurement methods, direct measurement method and natural frequency measurement method, are proposed in this paper. Then, based on the real data of experiment and field measurement, the vibration signals of typical insulation fault and mechanical fault such as spike discharge and end cover looseness are compared, analyzed and summarized, and their respective data characteristics are extracted, which can provide the basis for the determination of GIS vibration fault types.

Refractive Index Measurement of Glass with Arbitrary Shape Based on Brewster’s Law and a Focusing Probe Beam

The refractive index is one of the most important parameters of optical glasses and has a significant effect on optical properties. The measurement of optical glasses, especially for optical elements such as lenses, is urgently needed. However, several presented methods require the immersion of the sample in liquid and provide indirect measurements, while others require structural parameters as priori knowledge, which is complex and time-consuming. In this study, a Brewster-Law-based direct and simple measurement method for the refractive index of glasses with arbitrary shapes is proposed, and a laser beam is focused on the surface of the sample as a probe. The incident angle of the chief ray is close to the Brewster angle. The reflected light is collected by an array detector. The refractive index is calculated from the minimum intensity position obtained with image processing. Additionally, a symmetric measurement scheme is proposed to improve the accuracy. Using these methods, a prism and four spherical lens samples with different refractive indices or radii of curvature are tested and error analyses are carried out. Results indicate that the accuracy can reach 10−4.

MACRO- AND MICRO-DISPERSION OF SILICA IN TIRE TREAD COMPOUNDS: ARE THEY RELATED?

ABSTRACT The dispersion of rubber fillers, such as silica, can be divided into two categories: macro- and micro-dispersion. Both dispersions are important; however, to achieve the best reinforcement of rubber, micro-dispersion of silica is crucial. The common view is that these filler dispersions are strongly related. The micro-dispersion is understood as the consequence of the continuous breakdown of filler clusters from macro-dispersion. Yet, a large problem is that an objective unequivocal direct measurement method for micro-dispersion is not available. In this study, a set of parameters is defined that are anticipated to have an influence on the micro- as well as the macro-dispersion. Mixing trials are performed with varying silanization temperature and time, different amounts of silane coupling agent, and by using silicas with different structures and specific surface areas. The degrees of micro- and macro-dispersion are evaluated by measuring the Payne effect as an indirect method for micro-dispersion and using a dispergrader for quantitative measurement of macro-dispersion. The results show that the filler dispersion processes happen simultaneously but independently. These results are supported by earlier work of Blume and Uhrlandt, who stated as well that micro- and macro-dispersion are independent. The major influencing factors on micro- and macro-dispersion of silica are also identified.

Production of Chlorella vulgaris Biomass in Tubular Photobioreactors during Different Culture Conditions

Biomass of microalgae and the components contained in their cells can be used for the production of heat, electricity, and biofuels. The aim of the presented study was to determine the optimal conditions that will be the most favorable for the production of large amounts of microalgae biomass intended for energy purposes. The study analyzed the effect of the type of lighting, the time of lighting culture, and the pH of the culture medium on the growth of Chlorella vulgaris biomass. The experiment was carried out in vertical tube photobioreactors in three photoperiods: 12/12, 18/6, and 24/0 h (light/dark). Two types of lighting were used in the work: high-pressure sodium light and light-emitting diode. The increase in biomass was determined by the gravimetric method, by the spectrophotometric method on the basis of chlorophyll a contained in the microalgae cells. The number of microalgae cells was also determined with the use of a hemocytometer. The optimal conditions for the production of biomass were recorded at a neutral pH, illuminating the cultures for 18 h a day. The obtained results were 546 ± 7.88 mg·L−1 dry weight under sodium lighting and 543 ± 1.92 mg·L−1 dry weight under light-emitting diode, with maximum biomass productivity of 27.08 ± 7.80 and 25.00 ± 5.1 mg·L−1∙d−1, respectively. The maximum content of chlorophyll a in cells was determined in the 12/12 h cycle and pH 6 (136 ± 14.13 mg∙m−3) under light-emitting diode and 18/6 h, pH 7 (135 ± 6.17 mg∙m−3) under sodium light, with maximum productivity of 26.34 ± 2.01 mg·m−3∙d−1 (light-emitting diode) and 24.21 ± 8.89 mg·m−3∙d−1 (sodium light). The largest number of microalgae cells (2.1 × 106) was obtained at pH 7 and photoperiod of 18/6 h under sodium light, and 12/12 h under light-emitting diode. Based on the results, it can be concluded that the determination of the optimal parameters for the growth and development of microalgae determines the production of their biomass, and such research should be carried out before starting the large-scale production process. In quantifying the biomass during cultivation, it is advantageous to use direct measurement methods.

Beach Topography Surveying Using Unmanned Aerial Vehicle Photogrammetry Technology

The mechanisms of in situ topography changes must be identified for spatial planning in coastal areas. In this study, the authors used in situ direct measurement methods and indirect remote-sensing technologies to develop a method for beach topography surveillance. Unmanned aerial vehicles (UAVs) have advantages of high portability and mobility and low operating altitude. Therefore, a UAV was equipped with a lightweight camera and a positioning system that comprised a global positioning system and an inertial measurement unit. Aerial photogrammetry and aerial triangu-lation methods were adopted for matching image feature points to obtain the corresponding topographic points in the sand. A virtual base station with real-time kinematic positioning functionality was used to measure the coordinates of the ground control points for correcting the actual coordinates to obtain actual topographic points of the beach sand. The results obtained using image-matching point clouds and direct measurements were compared. The ground sample distance of a UAV at the operational altitude of 70 m was 3.26 cm. Moreover, the average elevation error was 3.20 cm, and the root mean square error was 0.169 m. The measurement error was ±25 cm, which was within the acceptance criteria of±50 cm set by Water Resources Agency, Ministry of Economic Affairs, Taiwan. UAV imaging technology can increase the efficiency of conventional manual sampling and reduce the cost of indirect observations, thus minimizing the measurement errors and field measurement costs.

Effects of long-term nitrogen fertilization on N2O, N2 and their yield-scaled emissions in a temperate semi-arid agro-ecosystem

Nitrous oxide (N2O) measured simultaneously with di-nitrogen (N2) emissions from soils are greatly uncertain due to large temporal and spatial variations. This study aims to report N2O, N2, N2/N2O, 15N-N2O, wheat-maize annual grain yields, and yield-scaled N2O and N2O plus N2 emissions on the responses to different nitrogen (N) fertilizer rates in a winter wheat-summer maize cropping system. Furthermore, this study also seeks to determine controlling factors for N2O, N2, and N2/N2O emissions and significantly investigate the relationship between the soil-climate measured factors and 15N-N2O. Three N inputs and control treatments, 0, CK; 200, LN; 400, MN; and 600, HN kg N ha−1 year−1 were set since 1998. Direct measurement method has been used to quantify N2O and N2 emissions. Our results indicated that the effects of long-term N fertilization significantly increased N2O and N2 and also reduced N2/N2O emission ratios as described by exponential functions. Using structural equation modeling (SEM), NH4+, WFPS, NO3-, and DOC were revealed to be main controlling factors for N2O, while N2 by DOC, NO3-, WFPS, and temperature finally N2/N2O was positively related to temperature. Furthermore, the 15N-N2O was positively related to N2/N2O ratios, indicating that denitrification is the dominant process at the study site. The yield-scaled N2O emissions followed the order HM>MN>LN>CK, and they were 1.56, 1.47, and 1.07 times greater than CK, respectively. Total yield-scaled N2O plus N2 were in the order of CK>HN>MN>LN. N fertilization has shown strong impact not only on N2O, N2, and N2/N2O emissions but also on yield-scaled N2O and N2O plus N2 emissions. High agronomic nitrogen use efficiency (NUE), low yield-scaled N2O emissions, and low cumulative N2O plus N2 emissions were observed at 200-LN treatment, suggesting this rate to be an optimum and sustainable agricultural management practice with no significant crop yield reduction as compared to the current farmers’ practice of 400 kg N ha−1 year−1.

Determination of the class of steel by small samples

Introduction. The data of the results of the inspection of steel structures are given, based on the analysis of which strength classes of structural steels are established. The goal has been solved by determining the chemical composition of metal structures and full-scale tests of the mechanical characteristics of steel structures, followed by a calculated conversion of the hardness index HB to the value of temporary tensile strength σv.
 
 Materials and methods. Strength indicators of metal structures are determined by non-destructive express method by means of a portable hardness tester of the dynamic principle of action. For the calculated determination of the breaking strength σv adopted the average lengthening coefficient kδ. By its value, the indicators of elongation and contraction are established, as well as the yield strength of the metal. Based on the calculated standard indicators of plasticity (δ, ψ) and strength (σv, σt), the complex criterion C equation is compiled. Using it, calculated the uniform elongation δр and the transverse narrowing ψр, which were used to assess the tensile strength (Sv, Sk) and fatigue (σ–1, τ–1).
 
 The chemical composition of small-sized samples in the form of metal shavings was determined by x-ray fluorescence. Additionally, the chemical composition of the steel was monitored using a scanning microscope with an attachment for determi­ning the chemical composition by energy dispersive x-ray spectroscopy.
 
 Results. The proposed research method makes it possible to conduct full-scale tests of metal structures and reduces the complexity of the selection and delivery of samples for laboratory research. The results obtained by both methods are correlated with the source data (design documentation for the object of the survey).
 
 Conclusions. An integrated method of sampling and direct measurement of hardness on site allows one to determine the chemical composition of metal structures, the grade and type of structural steel and its mechanical properties. At the same time, the scientific novelty is the given technique as a whole, which is characterized by a significant reduction in labor costs and minimization of damage to the objects under study.

STUDY OF PECULIARITIES OF PEDAGOGICAL CONTROL OF PUPILS 'TRAINING

The aim of the work was to study the features of pedagogical control of schoolchildren's learning in a modern general education school. Research methods: theoretical: a review of psychological and pedagogical literature on research issues. The advantages of the system for assessing the degree of training are that each subsequent parameter is qualitatively higher than the previous one, and the system as a whole assesses the growth of knowledge and skills of students and the proposed parameters are convenient to operate in practice during the current assessment of knowledge, skills and abilities of students. The disadvantage of the system - the last parameter - "transfer" - characterizes as the student's ability to solve problems of a heuristic and creative type, ie. this stage requires detailing. The teaching function of control is to determine the content, techniques and methods of control, which are educational in nature. Any controlling task, except for the controlling function, trains students in the implementation of specific educational actions, ensuring a more solid mastery of these actions. The controlling task includes an element of novelty in the informative and substantive terms, providing an expansion of the cognitive horizons of students, developing and increasing the learning value of control. It is difficult to eliminate the subjective element of pedagogical control due to various circumstances: the designation of learning outcomes is rather arbitrary: knowledge, abilities, skills, assimilation, academic performance, etc .; methods of direct measurement of educational activity have not been developed, and it is judged indirectly by the answers, by the actions of students. Pedagogical control is an important component of the educational process that influences the result, the course of training and education. This problem is one of the most urgent in teaching practice.

Development of Parameters for Standardization of Duckweed (Lemna Minor L.) Raw Material

Introduction.Lemna minor L. (duckweed) refers to the duckweed subfamily (Lemnaceae S. F. Gray) and widely distributed in ponds of Russia. Literature data confirm the possibility of harvesting significant volumes of this raw material in natural habitat and grown in aquaculture. The process of biosynthetic accumulation in duckweed fronds provides a variety of compounds with a wide spectrum of biological activity. Therefore, the use of raw materials Lemna minor L. is promising for the development of drugs and parapharmaceutical products. Thus, it is an urgent task to quantify active components of duckweed and standardize (determination of criteria for identification, quality and safety) plant material.Aim.Establish macro- and microscopic characteristics of raw materials and develop methods for the quantitative determination of the main groups of biologically active substances (BAS) for standardization of raw duckweed.Materials and methods.Samples of duckweed was collected in natural habitats of Western Siberia. Macro- and microscopic assay, HPLC, UV-spectrometry were used in research process.Results and discussion.Were established the criteria for identification of duckweed fronds by studying external (macroscopic) and microscopic features of raw material Lemna minor L. Was developed and validated the procedure of the quantitative determination of phenolcarboxylic acids in raw material Lemna minor L.Conclusion.The study of external (macroscopic) and microscopic features provided the criteria for identification of the raw material Lemna minor L. The technique for the quantitative analysis of polysaccharides using gravimetry does not need validation, because is a direct method of substance measurement. Was validated quantification method of phenolcarboxylic acids (in terms of chlorogenic acid) by criteria of linearity, repeatability, in-laboratory precision and accuracy. Was established quality criteria for identification and quantitative assay, which can be used in the draft for normative documents for medicinal plant raw material of Lemna minor L. «Duckweed fronds».

Tqix: A toolbox for Quantum in X: X: Quantum measurement, quantum tomography, quantum metrology, and others

We present an open-source computer program written in Python language for quantum measurement and related issues. In our program, quantum states and operators, including quantum gates, can be developed into a quantum-object function represented by a matrix. Build into the program are several measurement schemes, including von Neumann measurement and weak measurement. Various numerical simulation methods are used to mimic the real experiment results. We first provide an overview of the program structure and then discuss the numerical simulation of quantum measurement. We illustrate the program’s performance via quantum state tomography and quantum metrology. The program is built in a general language of quantum physics and thus is widely adaptable to various physical platforms, such as quantum optics, ion traps, superconducting circuit devices, and others. It is also ideal to use in classroom guidance with simulation and visualization of various quantum systems. Program summaryProgram Title:tqix: A toolbox for Quantum in XX: Quantum measurement, quantum tomography, quantum metrology, and others.CPC Library link to program files:https://doi.org/10.17632/wxvncw5jkv.1Developer’s repository link:https://vqisinfo.wixsite.com/tqixCode Ocean capsule:https://codeocean.com/capsule/0814109Licensing provisions: GPLv3Programming language: PythonExternal routines: NumPy, SciPy, Matplotlib.Nature of problem:tqix is an open-source program providing some convenient tools for quantum measurement, quantum tomography, quantum metrology, and others.Solution method: For quantum measurement, the von Neumann formalism and weal measurement have been used, where the measurement results can be obtained analytically or numerically (simulation) via various back-ends, including the Monte Carlo (mc) and Cumulative Distribution Function (cdf). There is also built-in quantum state tomography using the direct state measurement method, and some common tools for studying quantum metrology.

Statistična analiza primarnih meddendritnih prostorov v monokristalni superzlitini

Three generations of single-crystal superalloys (AM3, DD5 and DD90) were produced with directional solidification and seeding. The square-calculation method and direct-measurement method were used to study the primary-dendrite spacings of the three single-crystal superalloys at different solidification distances (50, 150 and 250) mm. Statistical results showed that, firstly, as the solidification heights increased, the average primary-dendrite spacings of the three alloys were gradually enlarged; secondly, the average primary-dendrite spacings calculated with the square-calculation method and the direct-measurement method were similar, which indicated the high precision of the two methods; thirdly, the primary-dendrite spacings of the three alloys were distributed randomly in a relatively large range, following a normal distribution. The maximum values of the primary-dendrite spacings were 4.7–8.5 times larger than the minimum ones at different solidification distances and were different from the values from previous studies.

Analysis of wave measurements in November 2018, January 2019, and March 2019 in the coastal waters of Leupung and Lhoong, Aceh Besar District, Indonesia

The coastal waters of Leupung and Lhoong Aceh Besar District are directly adjacent to the Indian Ocean. They play a major role in fishing and tourism activities. Thus, the study of ocean waves is important to conduct. The research aims to describe the variations of waves, i.e., height and period. The research was carried out in Leupung at station 1 and Lhoong at station 2 in November 2018, January 2019, and March 2019. The height and period of the waves were collected from 2 station points located at Leupung and Lhoong beaches, using the direct measurement method, that is, a scale meter to measure the wave height and a stopwatch to measure the wave period before the breaking wave. The results show that the wave height and period in November 2018, January 2019, and March 2019 in Leupung coastal waters are 0.42 m, 12.34 s; 0.5m, 12.43 s; 0.49 m, 13.82 s, respectively. Meanwhile, wave height and period in Lhoong coastal waters are 0.26 m, 12.31 s; 0.44 m, 13.97 s; 0.48 m, 12.22 s, respectively. It is concluded that the highest wave occurred in January and March 2019 at Leupung and Lhoong coastal waters, respectively. On average, the highest wave of the three months occurred in Leupung coastal waters.

Parameter Measurement and Calibration in Discrete Element Simulation of Broken Sweet Potato Seedlings

Given the lack of accurate parameter values in discrete element simulation of sweet potato seedling mechanized recovery, a direct measurement and virtual calibration method was used to study the Discrete Element Method (DEM) simulation parameters of broken sweet potato stems and leaves. The intrinsic parameters, collision recovery coefficient and static friction coefficient of broken seedlings were acquired by physical experiments. Different parameter combinations were designed for DEM simulation. The intrinsic parameters of sweet potato leaves and other unmeasurable DEM simulation parameters were determined by stacking angle optimization simulation. Plackett-Burman test shows that the static friction coefficients of stem-stem and stem-steel and the rolling friction coefficients of stem-stem and stem-leaf all significantly influence the accumulation angle. The parameters that significantly influence the stacking angle of broken seedlings were sent to steepest ascent test and Box-Behnken test. The average stacking angle of 40.51° and the relative error of 0.972% indicate it feasible to calibrate DEM parameters by physical test and optimization simulation and the calibrated parameters can be used in DEM simulation of broken sweet potato stems and leaves.

Hysteresis, latent heat and cycling effects on the magnetocaloric response of (NiMnSi)0.66(Fe2Ge)0.34 alloy

In this work, we further analyze the promising magnetocaloric (NiMnSi)0.66(Fe2Ge)0.34 alloy, which presents isothermal entropy change values as large as 29 J kg−1 K−1 for 2 T at room temperature. It undergoes a magnetostructural transition accompanied by large thermal/magnetic hysteresis, which remains up to high magnetic fields (corroborated by the elaboration of an experimental magnetic phase diagram). We illustrate that this huge hysteretic behavior (i.e. different responses when magnetizing or demagnetizing) can lead to erroneous interpretation of the order of the phase transition by applying the conventional Banerjee's criterion or the recently developed field dependence analysis of the magnetocaloric effect. Additionally, the cyclability of the response is characterized, showing that after several measurements the magnetocaloric response is significantly reduced (by ≈ 40%) due to sample breaking. These dependences together with the large latent heat of the transition (15.0 kJ kg−1) lead to relatively small values of the adiabatic temperature change for powdered samples at moderate field changes, reaching around 0.6 K for 1.75 T by direct measurement methods.

Research on developing a methodto estimate fugitive CH4 emissionfactors of coal surface mining in Quang Ninh province

This article presents the approach and the results of estimating CH4 emission from surface mining in Quang Ninh province to develop its fugitive CH4 emission factors. The two largest active surface mines were selected named Nui Beo and Cao Son. By applying a direct measurement method with samples using a specific chamber, CH4 emission was collected and calculated for the whole mine. Results showed that CH4 emission varied from mine to mine both the total amount and its range of maximum and minimum. In detail, the total amount of CH4 emission from Cao Son is 19,032.87 m3with the range of 73.14% while these numbers of Nui Beo are 2,684.47 m3 and 76.38%, respectively. The CH4emission factors of surface mines then were estimated in the range of 0.0850 m3/ton and 0.0225 m3/ton respect to high emission level and low emission level. These values are close to the emission factors generated from Germany (0.015 - Lignite), Canada (0.088 - Lignite; 0.19 - Bituminous), South Africa (0.002÷0.064 - Bituminous). These emission factors are considered as scientific evidence to propose the national factors of CH4 emission of surface mining.

Mapping of inhomogeneous quasi-3D electrostatic field in electro-optic materials

This paper describes a new method for direct measurement and evaluation of the inhomogeneous electrostatic vector field with translational symmetry in electro-optic materials exhibiting the Pockels effect. It is based on the evaluation of maximum transmittance of low intensity light passing through a sample under a voltage bias. Here, the sample is located between rotating crossed polarizers, and camera images are obtained at each point to determine the electric field. The evaluation procedure is demonstrated using data acquired on a CdZnTeSe quasi-hemispheric semiconductor gamma-ray detector. In addition to CdTe-related compounds, the method can be used for various other materials showing overline{4}3m symmetry such as GaAs, CdTe, GaP, 3C-SiC, and ZnS. Furthermore, it can be generalized to other crystalline materials showing the Pockels effect. The method can be used to probe the space charge and the electric field in several kinds of electronic components and devices, as well as provide useful data on the role of defects, contact configurations and other surface and bulk inhomogeneities in the material that can affect the distribution of the internal electric field.

A novel test device for the direct measurement of tensile strength of rock using ring shape sample

A novel test method is proposed in this research for determining the tensile strength of rocks and geo-materials. Using a seesaw device, two diametral tensile forces are applied to the inner surface of a ring shape specimen and consequently the ring specimen is splitted along a plane normal to the direction of applied tensile loading. A suitable formulation was derived for determining the tensile strength value using the direct ring tension specimen tested with the seesaw device. The required shape factor for the suggested tensile strength relation was obtained from the finite element analyses of ring specimen with different inner and outer diameters. The practical ability of suggested direct tensile strength measurement method was examined by performing some tensile strength experiments on tuffite rock and it was found that the results obtained from this test method is in very good agreement with two other conventional indirect tensile strength testing methods namely the Brazilian disc and compressed ring tests. Suitable geometry (i.e. inner/outer diameter ratio) was also proposed for testing the ring specimen. In addition, the fracture patterns of direct and indirect ring specimens tested with different di/do ratios were simulated and predicted using the XFEM method.

Direct measurement of the effect of non-submerged rigid vegetation-induced flow cross-section area variations on flow force in compound channel

In this experimental work, flow force in compound channel in presence of non-submerged vegetation was obtained via direct measurement method. The direct measurement method was used to address the inefficiency of the conventional energy-based methods for measuring the force within the body of highly rough flows. On this basis, the study was performed using a specially designed flume called knife-edge flume with a length of 14 m, a width of 1.07 m, and a height of 1.05 m at a stream bed grade of 10-3. The flow force measurements were performed directly using a load cell in absence of the common errors that were otherwise associated with velocity measurement by inserting an external body into the flow. In this study, we examined non-submerged rigid vegetation layers with five different diameters (i.e., 20, 25, 30, 40, and 50 mm), three values of crossline spacing (i.e., 6, 8, and 10 cm), five values of crossline spacing (i.e., 8, 10, 12, 15, and 20 cm), and two different arrangements (i.e., ordered and non-ordered or cruciform) at three different positions (i.e., in the floodplain, in the main channel, and simultaneously in the floodplain and the main channel) by performing a total of 451 tests. The flow force exhibited the highest sensitivity to the increase in vegetation volume under the non-ordered arrangement. In this respect, the improvement in the flow force with increasing the percent volume of vegetation was much larger when the vegetation was arranged in a non-ordered rather than ordered fashion, with the effect of the vegetation been even more pronounced in the floodplain rather than the main channel. In addition, at a certain percent change of the flow force, the trough-vegetation flow velocity was higher under the ordered arrangement rather than the non-ordered arrangement, reflecting the more difficulty encountered by the flow as it passed through the non-ordered vegetation. Based on the analysis results, it was found that the flow force would change by 060% when the vegetation had grown in the floodplain with λ* values in the range of 0–1. In cases where the vegetation had grown in the main channel and simultaneously in the main channel and the floodplain, the flow force variations increased to 10–70% and 20–80% as the λ* changed from 0 to 10, respectively. Analyzing the results of the experiments and the vegetation-modified Reynolds number, a relationship was further presented for calculating the flow force in presence of non-submerged rigid vegetation in a compound channel.

MULTIPURPOSE MEASUREMENT MODELS FOR ADJUSTMENT BY THE LEAST-SQUARES METHOD

The development of multipurpose measurement models is the precondition for software development for simultaneous adjustment of the large scope and complicated combinations of the measurement results by the least-squares method. Multipurpose measurement models for software can be a helpful tool for processing the final measurement results provided by different measurement methods applying the mentioned software; processing the measurement results of measurement standards comparisons, interlaboratory comparison, and calibration procedures; estimating the additive and multiplicative systematic components of measurement errors and their uncertainty; processing complicated combinations by binding or linking up of the interlaboratory comparison and calibration results in the time; simultaneous processing of the measurement results obtained by various methods e.g. by the method of direct measurements and comparisons; fast-changing the multipurpose measurement models from linear to non-linear type. Processing of the results by software based on the multipurpose measurement model algorithm can help to established a comprehensive measurement traceability network by pooling the single traceability chains.

Experimental Assessment of High Frequency Bearing Currents in an Induction Motor Driven by a SiC Inverter

Compared with silicon (Si) IGBTs, silicon carbide (SiC) MOSFETs have much faster switching speeds and high switching frequency operation capability, enabling compact and high-efficiency motor drive systems. However, the increased switching speed and frequency also cause increased-level of common-mode (CM) voltage with higher slew rates ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dv</i> / <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dt</i> ). The CM voltage leads to machine leakage currents as well as bearing currents such as electric discharge machining (EDM) type current and capacitive-type ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dv</i> / <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dt</i> ) current. These bearing currents can cause degradation or failure of motor bearings. In order to investigate the impact of SiC motor drives on the motor bearing currents, in this paper, the mechanism and modelling of bearing currents are analyzed first. Then, a direct measurement method is used to assess the bearing currents in the induction motor driven by the SiC converter. In the experiment, the number of EDM current events is counted and the amplitude of the capacitive-type of current is also examined under various switching speeds and frequencies of SiC devices. Furthermore, the bearing currents are also extensively tested under various bearing temperatures, motor speeds and dc-link voltages. The correlations between the bearing currents and various factors have been revealed in this paper.