A comprehensive analytical subdomain model and its field solutions for surface-mounted permanent magnet machines

This paper presents a comprehensive analytical subdomain model together with its field solutions for predicting the magnetic field distributions in surface-mounted permanent magnet (PM) machines. The tooth tips and slotting effects during open-circuit, armature reaction, and on-load conditions are considered when deriving the model and developing its solutions. The model derivations and field solutions are extended from a previous model, and can be applied to PM machines with any combinations of slot and pole numbers and any magnetization patterns in the magnets. This model is initially formulated according to Laplace's and Poisson's equations in 2-D polar coordinates by the separation of variables technique in four subdomains, such as magnet, airgap, winding slots, and slot-openings. The field solution of each subdomain is obtained applying the appropriate boundary conditions and interface conditions between every two subdomains, respectively, which can precisely account for the mutual influence between slots. Finite element analysis (FEA) is later deployed to validate the analytical results in a surface-mounted PM machine that has nonoverlapping winding arrangement. For validation purposes, PM machines having 3-slot/2-pole with parallel magnetization and 12-slot/10-pole with either parallel or radial magnetizations are used for comparisons. Computation of global quantities for the motor which include the phase back-EMF and cogging torque is also included. The results indicate that the proposed analytical model can accurately predict the magnetic field distributions in each subdomain and the motor's global quantities, which are in good agreement with those obtained from the FEA.

I can see clearly now the moderating effects of role clarity on subordinate responses to ethical leadership

© Emerald Group Publishing Limited. Purpose – Although there is growing research on the relationship between ethical leadership and subordinate work behaviors, limited research has examined the boundary conditions under which ethical leadership is more or less effective. The purpose of this paper is to investigate whether subordinate perceptions of role clarity in their job role influence the relationship between ethical leadership and subordinate work behaviors. Drawing on both social exchange and social learning theories, the authors predict that in contexts where subordinates perceive low levels of role clarity, the relationship between ethical leadership behavior and subordinate helping and deviant behaviors will be weaker. Design/methodology/approach – In total, 239 employees in the Chinese public sector completed surveys across three separate time points. Confirmatory factor analysis and hierarchical regression analysis were used to analyze the data. Findings – Analyses provided support for the hypothesized relationships. When subordinates perceived higher levels of role clarity the positive relationship between ethical leadership and helping behavior was stronger, and the negative relationship between ethical leadership and deviant behavior was stronger. Research limitations/implications – As with all research the findings of this study need to be viewed in light of its limitations. First, the use of data from a single set of respondents opens up the possibility of common method bias. Second, given the study used of a sample of public sector employees from one part of China, there would be value in future research examining whether the findings from the present study are generalizable to other industrial and cultural contexts. Practical implications – This research has a number of practical implications. Given that the authors found a significant positive relationship between ethical leadership and helping behavior, and a significant negative relationship between ethical leadership and deviant behavior, it is crucial for organizations to include ethical training as an essential part of leadership development programs. However, the findings also suggest at the same time as facilitating the development of ethical leadership behaviors amongst supervisory employees, it is important for organizations to also provide employees with clarity over what is expected of them in their jobs, and the means they should employ to facilitate goal achievement. Originality/value – This study responds to recent calls for more research to identify factors which may strengthen or mitigate the influence of ethical leadership in the workplace.

How servant leadership influences organizational citizenship behavior: the roles of LMX, empowerment, and proactive personality

© 2015 Springer Science+Business Media Dordrecht While the link between servant leadership and organizational citizenship behavior (OCB) has been established, the individual-level mechanisms underlying this relationship and its boundary conditions remain poorly understood. In this study, we investigate the salience of the mediating mechanisms of leader–member exchange (LMX) and psychological empowerment in explaining the process by which servant leaders elicit discretionary OCB among followers. We also examine the role of followers’ proactive personality in moderating the indirect effects of servant leadership on OCB through LMX and psychological empowerment. Analysis of survey data collected from 446 supervisor–subordinate dyads in a large Chinese state-owned enterprise suggests that while servant leadership is positively related to subordinate OCB through LMX, psychological empowerment does not explain any additional variance in OCB above that accounted for by LMX. Moderated mediation tests confirm the moderating effect of proactive personality through LMX. By providing a nuanced understanding of how and when servant leadership leads followers to go above and beyond their job role, our study assists organizations in deciding how to develop and utilize servant leaders in their organizations.