Linear Electric Machines, Drives, and MAGLEVs Handbook

5 Design of Flat and Tubular Low-Speed LIMs

5.1 Introduction

Low-speed LIMs are LIMs whose dynamic end effects can be neglected [(γ_2r τ)⁻¹ < 2 p/10] (as described in Chapter 3). They have to be designed, consequently, for a goodness factor less than the optimum value G_e0 (Chapter 3), which varies linearly with the number of poles 2p (G_e = 10 for 2p = 4 and G_e = 40 for 2p = 16).

Though we are intuitively tempted to assimilate low speed with low goodness factor and thus end effect neglection, the situation is more complex, as in principle we could obtain the same equivalent goodness factor G and thus the same end effect (for the given pole count and slip), for up to 3/1 speed ratio [1].

So, we should choose for a low-speed application a low ...