Rockwell Automation (Germany)

The vast majority of bearing failures in electric motors and electric motor-driven equipment are due to mechanical and thermal causes. Bearing current in induction motor can result in premature bearing failure. Proper remediation methods depend upon a thorough understanding of the potential current paths in a given installation. Diagrams of current flow paths were presented here to illustrate potential issues. Proper grounding is a key to shunting currents away from paths that flow through motor or driven equipment bearings.

A 2-D computational study of flow over a fully open sunroof of a car with a passenger compartment has been done on a scalar workstation. The critical velocity for resonance in the passenger compartment has been determined. A wind deflector angle study has been done to determine an adequate angle to suppress the resonance. A validation case of computing the resonance condition of the flow over a 3:1 depth to length rectangular cavity has also been done. These resonance studies show the potential of using scalar workstations for a CFD design study.

The World Economic Forum predicts that digital transformation initiatives will lead to more than $320 billion of value for the mining and cement industries, a 610 million ton reduction in CO2 emissions, and 1,000 lives saved as worker safety improves. But no one is talking about the fact that most digital transformation initiatives fail before they're fully implemented. The problem isn't isolated either: a recent Gartner study showed that across all market segments, 85% of big data projects fail. How can a company `go digital' safely? This paper will examine the main roadblocks encountered in digital transformation projects: From lack of holistic vision and clear definition of corporate digital strategy, to talent deficits, failure to plan for scalability, and internal resistance to change. We will share some simple ideas that work for our customers, provide information about `ready-to-implement' technologies, and help construct a basic roadmap for implementing digital transformation projects.

DeviceNet and ControlNet are two well known members of the same family of protocols - the CIP family (CIP=Control an Information Protocol). Both protocols have been developed by Rockwell Automation, but are now owned and maintained by the two manufacturers organizations ODVA (Open DeviceNet Vendors Association, see http://www.odva.org) and ControlNet International (see http://www.controlnet.org/). ODVA and ControlNet International have recently introduced the newest member of this family - Ethernet/IP ("IP" stands for "Industrial Protocol"). This paper describes the basics of CIP and gives an overview over the newest member of this family of protocols - Ethernet/IP.

The predicted performance of a three-lobe journal bearing with a preload factor of 0.75 is compared with the measured performance. Operating eccentricity and dynamic coefficients versus Sommerfeld number are compared for three shaft speeds and various steady loads. Numerical results are based on a model which solves the Reynolds equation and allows for a variety of thermal effects including circumferential and cross-film viscosity and temperature variation. The linearized coefficients are experimentally determined by an average magnitude and phase method using synchronous, sinusoidal excitations. Comparisons of journal position show good agreement (within 9.5%) for Sommerfeld numbers below 0.7 and increasing disagreement (30 % or greater) at higher Sommerfeld numbers. Agreement in journal position improves as load and shaft speed increase. At Sommerfeld numbers less than 0.4 to 0.7, agreement between the numerical and experimental dynamic coefficients is very good, typically within the uncertainty of the measured data. The magnitude and slope of the coefficients vs. Sommerfeld number match well. Disagreement in coefficient magnitude by as much as 100% is seen at high Sommerfeld numbers, although there is general agreement in the trend for predicted coefficients vs. Sommerfeld number.

Abstract In this article, a cascade controller is designed and analysed for a non-inverting buck–boost converter. The fast inner current loop uses sliding mode control. The slow outer voltage loop uses the proportional–integral (PI) control. Stability analysis and selection of PI gains are based on the nonlinear closed-loop error dynamics incorporating both the inner and outer loop controllers. The closed-loop system is proven to have a nonminimum phase structure. The voltage transient due to step changes of input voltage or resistance is predictable. The operating range of the reference voltage is discussed. The controller is validated by a simulation circuit. The simulation results show that the reference output voltage is well-tracked under system uncertainties or disturbances, confirming the validity of the proposed controller. Keywords: SMCPIclosed-loopnonminimum phasetransientnon-inverting buck–boost converter

The measurement of direct shaft torque and its transduction to various forms of signal is a primary interest of many electric machine builders and process application end users. Since torque multiplied by the instantaneous shaft rotational speed is the instantaneous power being delivered to the product and its integration over time the delivered process energy, the use of torque transduction to indicate everything from delivered mass of product to the energy change necessary to produce the proper change of state in a mix has increased dramatically. This paper reviews the basic methods and applications of torque sensing and transduction in industrial applications and provides comparison of their relative operational characteristics and performance. Nondirect methods such as inferred torque (i.e., reaction strain gage) are compared to direct methods such as "torduction". It is shown that the recent advances in noncontact types of direct torque measurement have made them a more practical choice for many industrial applications where speed of response is a dominant consideration, but the indirect methods must be carefully considered in comparison because of higher steady state accuracy, durability, and reduced cost.

This work focuses on non-linear characterization of 61-channel electroencephalogram (EEG) signal for detecting alcoholics using ranked Approximate Entropy (ApEn) parameters. Significant channels that contribute to the detection of alcoholism are selected by ranking the ApEn features based on ANOVA test. In order to classify alcoholics from control, the ranked feature set is applied to two non-linear classifiers, namely Back Propagation Neural Network (BPNN) and Support Vector Machine (SVM) Classifiers respectively. The performance of the classifiers is evaluated in terms of classification accuracy as well as computational processing time. Experimental results reveal that the BPNN classifier with 40 hidden neurons and SVM classifier with a polynomial kernel of order 3 perform with an accuracy of 90% with only 32 ranked ApEn coefficients.

Due to the rising number of heart patients and the apparent need for more robust electrocardiogram (ECG) monitoring of these patients, hospitals are increasingly investing in typical cloud technology or centralized hospital server based remote ECG monitoring systems. However, the deployment these systems in rural communities is limited due to the high cost factor. To counter this challenge, in this paper, we focus on the design and implementation of a low cost real time wireless ambulatory ECG monitoring system. The detected ECG signals are first filtered and amplified and then digitally converted by a microcontroller. The digitized ECG signals are then sent over a ZigBee wireless link to a gateway personal computer (PC) at patient’s premises. The received ECG data from the ZigBee connection is displayed in real time via the National Instruments (NI) Laboratory Virtual Instrument Engineering Workbench (LabVIEW) user interface on the PC for instant personalized evaluation of the ECG data. The ECG data can be saved on the PC and sent via email to a remote cardiologist or a clinician. Additionally, the gateway PC at patient’s end acts as web server for sharing patient’s data over the Internet. The remote off-site physician (medical staff in a hospital) can use a web browser on a PC, laptop or a mobile phone with Internet connection to access patient’s real time ECG trace for monitoring, expert review and diagnosis. It is shown that the system prototype allows users to acquire reliable ECG signals effectively and simply. The proposed ambulatory ECG system offers an alternative low cost deployment strategy and is especially suited for remote cardiac monitoring of patients in rural communities.

Integrated ship system control is a challenging domain as it involves a set of highly complex and interdependent systems, including electrical power, electric drive propulsion, high-energy weapon systems, various auxiliary systems, and an underlying communications network. Many of the high-level system management questions demanding answers for the electric ship power system and ship service are directly related to control system architecture. As we move toward more decentralized, hierarchical systems, much work remains to be done to optimally determine the appropriate level of control and intelligence at each tier of the architecture. The body of knowledge in this area is limited with respect to power systems and is only slightly more developed for ship service systems. There is a significant need not only to address methods and algorithms from the standpoint of pure decentralization but also to address ways to migrate these methods into an actual distributed, fault-tolerant supervisory control structure that meets the requirements for implementation on the electric ship.

Due to the inductor-capacitor filter, a pulse width modulation (PWM) current-source rectifier (CSR) may experience LC resonance. A smaller ratio between the switching frequency and the resonant frequency of the CSR presents a challenge in designing active resonance damping methods in high-power applications. In this paper, different feedback states of filter inductor current and capacitor voltage are investigated to damp out the LC resonances. Besides proportional capacitor-voltage feedback (CVF), the derivative inductor-current feedback (ICF) provides an alternative approach for active damping and is comprehensively analyzed. Compared with the virtual-resistance (VR) based active damping strategy, controller design is simpler in this method. The ICF based active damping strategy works well for current-source rectifiers with low switching frequencies. Simulation and experimental results verify the feasibility and validity of the method.

Bus capacitors play a critical role in the operation of Variable Frequency Drives (VFDs). Failure of bus capacitors can cause a failure of the drive leading to unplanned downtime and substantial revenue loss for customers. In VFDs, liquid aluminum electrolytic capacitors are used as bus capacitors for smoothing of voltage and when line can't provide large bursts of energy (drive start-up) and during temporary power loss. These liquid aluminum electrolytic capacitors are critical for the successful functioning of the VFDs for various customer applications. The VFDs are used across many industries such as paper, tire and rubber, oil and gas, and automotive. In order to select robust liquid aluminum electrolytic capacitors for the drives, reliability testing is critical. Liquid aluminum electrolytic capacitors have long been considered as the weakest reliability component in power electronic systems. Primary failure mechanism observed is evaporation of liquid electrolyte leading to a decrease in capacitance and increase in equivalent series resistance (ESR) and eventually causing the failure of the capacitor. Ripple current increases the core temperature of these capacitors which leads to capacitance drop and ESR increase and reduces the useful life of these capacitors. As ESR increases, the heating effects due to ripple current worsens and this turn into a runaway failure situation. Therefore, it is paramount to perform the reliability/qualification testing on these capacitors with ripple current at elevated temperature and DC voltage bias. Testing multiple capacitors with just DC voltage is simple (connecting several capacitors in parallel) but testing multiple capacitors with combined DC voltage and ripple current is a challenge. A special test setup was prepared using two sub-systems. The first sub-system included an auto transformer, a rectifier, and liquid aluminum electrolytic capacitors. Second subsystem included a variable frequency drive (VFD), a sine wave filter and a 3-phase transformer. The first sub-system provided the adjustable DC bias voltage. The second sub-system provided adjustable magnitude/frequency of AC ripple current. The detailed construction of the test setup is included in this paper. To select robust liquid aluminum electrolytic capacitors, the capacitors were tested using this test setup at rated temperature, rated ripple current plus DC voltage bias. Electrical parameters for the capacitors like capacitance, ESR and leakage current were measured before starting the test. These electrical parameters were monitored by measurement at regular intervals during the test. The test was stopped and after capacitors cooled down to room temperature, the measurements were taken. Testing liquid aluminum electrolytic capacitors before using them in the final product can greatly reduce the probability of field failures.

The number of ac drives present in the power systems of most industrial facilities has shown a significant increase in the past 3 decades, taking an important percentage of the total power demand. Two options to produce energy savings on these drives is the use of an optimized flux level, and the operation with reduced switching frequency. Paper reports the development of a complete loss model for vector controlled low-voltage ac drives, which includes all converter and motor loss components. Using this loss model, an algorithm is implemented to run detailed loss evaluations in the entire constant-torque zone. Four ac drives of 4 kW, 11 kW, 55 kW and 110 kW are evaluated considering switching frequencies of 1 kHz, 2 kHz, 4 kHz and 8 kHz. Results confirm that reducing the switching frequency from 8 kHz to 2 kHz produce interesting power savings, while keeping a low level of harmonic content and a safe operation of the ac drive.

This paper proposes a position sensorless control scheme for an induction and permanent magnetic motor drive with output filter and transformer. The proposed method provides sufficient starting torque with controlled drive/motor current. In addition, transformer saturation is addressed. The sensorless starting scheme presented in this paper has been implemented in a commercial drive for deep well applications.

Cement producers have faced a significant rise in energy costs with the introduction of dry-process kilns, with a record average consumption of 100-200 kwh per ton of cement (The Cement Plant Operations Handbook, 2009*). This complex challenge, coupled with rising fuel and energy costs, has prompted cement manufacturers to implement energy management programs to help reduce costs while maintaining competitiveness and increasing profits. This paper will review how many cement producers have reduced energy costs by adopting innovative sustainability programs. A holistic approach teaches a simple five-step process: audit, monitor; analyze; control and optimize. This practice helps customers to identify cost saving measures and evaluate the tools available which are best suited to their specific plant needs: power and energy management systems; variable frequency drives; model predictive control systems; energy audits; and others. Learn how other cement producers have reduced their energy costs by up to 20 percent by finding and eliminating operating inefficiencies, modifying equipment, driving energy efficiency in product design and modifying processes. Obtain the tools necessary to expand plant operations to include comprehensive energy management programs that will quickly provide measurable results and remarkable cost savings.

The objective of this work has been to propose a self-powered gate driver system for medium voltage solid state starters. This paper presents some experience with SCRs using the self-powered gate driver system (SPGDS), designed and used for starting and stopping large induction motors. The proposed system derives power for gating the SCR from energy stored in the snubber capacitors at turn on and the voltage across the SCR at turn off. This solution eliminates the need for an isolated power supply board or auxiliary power supply, with substantial savings in cost and space in MV applications.

Many pulp and paper operations use hardware-based Continuous Emissions Monitoring systems (CEMS) to track boiler emissions. This hardware approach uses pumps, filters and analyzing instruments to draw emissions from the combustion equipment and measure their levels. Using hardware can be costly and time consuming as it requires daily deployments of calibration gases to confirm the system is providing accurate measurements. And when CEM s fail, data blackouts can occur. In addition, the life span of hardware is short, averaging eight to 10 years. Due to these factors, more and more industrial operators are abandoning hardware in favor of software for emissions monitoring. This software approach is often referred to as a predictive emissions monitoring system (PEMS). This tutorial compares the hardware and software approaches, and features a boiler application case study to showcase the financial advantages of the software approach.

The Open DeviceNet Vendors Association (ODYA) is introducing an expansion to the DeviceNet specification that allows the integration of safety measures into all DeviceNet systems. DeviceNet Safety is designed to meet the requirements of machinery shut down and process sector availability/shut down applications. DeviceNet Safety addresses ISO 13849-1, IEC 61508 SIL 3, DIN 19250 AK6 and EM 954-1 Categoiy 4 applications. It is a higher level protocol that allows safety devices to co-exist with standard devices on the same network. DeviceNet Safety allows for multiple independent safety chains on the same network or controller as well as multiple safety controllers on the same network. DeviceNet Safety uses the safety processes and coding as recommended by BIA, the German certification body for safety data transmission on a standard network.

Synchronous motors continue to be a viable alternative to induction motors because of efficiency advantages. Long used for providing leading kVARs for PF improvement and helping with the device switching in Load Commutated Inverter (LCI) drives, these machines are efficient prime movers for large Mill applications. Both in motor efficiency and in low base speed configurations the synchronous motor has advantages of lower current and higher efficiency. Often used in large Mills in the cement and mining industry, these motors were driven by LCI variable-frequency drives (VFDs) or used with direct start with a clutch system that would synchronize the motor first to overcome low starting torques. This paper reviews various Mill drive configurations and improved synchronous motor characteristics when used with more advanced Current Source Inverter (CSI) drives. It will also review the different synchronous motor excitation types and resulting performance characteristics with VFD control for new or retrofit installations.

As graphical operator interfaces become more prevalent in our working world, it becomes increasingly important to focus on factors necessary to design the best screens possible. Recent improvements are generally due to advance in three major areas: increased understanding of the human factors involved in human-machine interface design; more effective operator interface deign; and improves operator terminal design and manufacture. In this paper, the author describes how human influence in screen design is an important, yet often neglected, consideration.