1,721,136 research outputs found
Bonded magnets for brushless fractional machines: Process parameters effects evaluation
No full textThe adoption of bonded magnets in substitution of ferrites in small PM motors is an interesting challenge and represents a good opportunity for motor designers. The proposed analysis regards the production of bonded magnets based on rare earth powder mixed with different resins; the effect of the process parameters, in particular the pressure on the mold, is evaluated by means of measurements on the magnets, FEM simulations and experimental tests on prototypes. The opportunity to vary also the resin percentage is briefly proposed as a glance on future developments of the work. © 2013 IEEE
Liquidity constraints in a monetary economy
No full textThis article presents a microfounded model of money with a consumption and an investment market. We consider an economy in which only part of the investment returns can be pledged. A liquidity constraint arises when the pledgeable part of the returns are not enough to pay for investment costs. We show that when the liquidity constraint is binding, agents may make a cash downpayment and money can perform two roles—as a provider of liquidity services and exchange services. The liquidity constraint constitutes a channel though which underinvestment occurs even at low inflation rates
Collateral secured loans in a monetary economy
No full textThis paper presents a microfounded model of money where durable assets serve as a guarantee to repay consumption loans. We study a steady state equilibrium where money and credit coexist. In such an equi- librium, a larger investment in durable capital relaxes the borrowing constraint faced by consumers. We show that the occurrence of over-investment and the behavior of capital accumulation depend on the rate of inflation, the relative risk aversion of agents and the marginal productivity of the capital goods
Collateral fluctuations in a monetary economy
No full textThis paper studies economy-wide fluctuations that occur endogenously in the presence of monetary and real assets. Using a standard monetary search model, we consider an economy in which agents can increase consumption, over and above what their liquid monetary asset holdings would allow, pledging real assets as collateral for monetary loans. It is shown that, if the liquidation value of real assets is below full market value, a stable cyclical equilibrium can emerge in consumption and capital around the unstable steady state. We also provide conditions for the existence of cycles of higher order, chaos and sunspot equilibria
Different Approaches in the Use of Ferrites in Assisted Reluctance Machines
No full textThe adoption of assisted reluctance machines in various applications is becoming popular. The use of permanent magnets in synchronous reluctance machines solves some drawbacks and improves the performance; in general, sintered magnets with regular shapes have been adopted. On the other hand, this approach does not permit to fill completely the flux barriers. The proposed solution consists of the use of bonded magnets. Two types of ferrite magnets, sintered and bonded, have been considered in the study. Different parameters have been investigated, both in the production process and in the performance evaluation. The simulation results have been compared to the reference synchronous reluctance machines. A prototype machine has been prepared, and different experimental tests have been performed. Satisfactory matching between measurement and simulation results has been observed
Liquidity externalities and the Wallace conjecture
No full textThis paper presents a pure currency economy with a nondegenerate distribution of money
holdings in which, as conjectured by Wallace (Quarterly Journal of Economics 129,
259–274, 2014), there are transfer schemes financed by money creation that improve ex
ante welfare relative to no-intervention. Differently from what was advocated by Wallace,
pecuniary-like externalities, rather than the need to share liquidity risks, are responsible
for the result
Study of the Compositions of Hybrid Magnetic Composite (HMC) Materials for Sensor Applications
No full textThe research being carried out nowadays on soft magnetic materials focuses on increasing the total efficiency of electromagnetic devices reducing the total losses. In this context, new magnetic materials are becoming increasingly important and could replace the traditional ones in many applications. In the field of electrical machines and filter inductances, the laminated sheets could be replaced, for some applications, with more energy-efficient materials. New compacted magnetic cores have been implemented adopting Soft Magnetic Composite (SMC) materials. Many advantages are obtained by the use of such materials: lower eddy currents and total iron losses at medium frequencies and the possibility to produce magnetic cores in very complex geometries. In this work innovative SMCs are implemented using organic layers to insulate and keep together the grains; the effect of the particle sizes on magnetic properties has been examined: specimens with small, medium and big granulometry have been made and fully characterised
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