Efficiency characteristics of linear dc motor by using a novel measuring method

摘要

This paper describes the efficiency characteristics of a cylindrical moving-coil-type linear dc motor (LDM) for compressor. Another linear motor is used as the load, and the load current, I{sub}L from ac power source is supplied to the load linear motor directly. The efficiency characteristics of the LDM for varying phase angle, θ, of the load current,{sub}L from the exciting current, I, is measured. Obtained results are as follows. (1) The efficiency, 17, increases with decreasing phase angle, θ. At the load current,{sub}L = 0.82 A, maximum efficiency is 55%. (2) The amplitude, X{sub}m, of the displacement becomes minimum value at the phase angle, θ= 1800. At the load current, I{sub}l of 0.82 A, amplitude, X{sub}m, is 3.0 mm. There is a decrease in the amplitude, F{sub}(Lm), of the load with decreasing phase angle, 0, but the efficiency, 17, increases because the phase angle, r+δ, between the displacement and load approaches 90℃。