Analysis of starting and synchronization process for line start IPM motors
This paper presents an improved analytical method for determining the synchronizing capability of a line start interior permanent magnet (IPM) synchronous motor. Approximate solution techniques based on average torque analysis for determining the critical slip and maximum inertia are also presented. A dynamic d-q axis model of the motor is developed to investigate the run-up response as well as synchronization capability of line start IPM synchronous motors. The start-up and synchronization performances of a 1hp 208V 4-pole line start IPM motor for various loads have been obtained using MATLAB. Experimental investigations have been also carried out for the same 1 hp IPM motor and test results are presented to support simulation results.
High efficiency line-start interior permanent magnet synchronous motors
This paper presents a successful design of high efficiency small but novel interior permanent magnet motor using NdBFe magnets. It is designed to operate both at line and variable frequencies. Line-start with high inertia load was a special consideration. Time stepping finite element analysis has been used to successfully predict the dynamic and transient performances of the prototype motors. It has been found that the proposed design has yielded successful simulation and experimental results. The maximum load inertia corresponding to the rotor-bar depth has been determined from the simulation results.
Laminar heat or mass transfer in rectangular channels and in cylindrical tubes for fully developed flow: comparison of solutions obtained for various boundary conditions
Abstract A comparison is made of results obtained with various boundary conditions at the wall of the channels. By comparing blood Sherwood numbers for finite wall resistance with those for constant concentration boundary condition only a small variation is found for various points along the blood channel.