A brushless dc motor has 3 phases and 4 poles. The generated emf is 220 V rms sinusoidal at 1000 rpm (open circuit voltage when tested as generator with a drive motor). Calculate (a) the emf constant (V/Rad/s); (b) the torque constant (Nm/A) with optimum position feedback angle; (c) the speed/torque curve, if the resistance per phase is 4 ; (d) the supply frequency at 1000 rpm; (e) curves of input power, output power and efficiency against torque, assuming friction and iron losses are zero; (f) the frequency and speed at which X= L is equal to the resistance R, if the phase inductance is 5 mH; (g) what is the effect of (f) on the speed/torque curve i.e. the effect of L>0 and L>R as speed increases?

A brushless dc motor has 3 phases and 4 poles. The generated emf is 220 V rms sinusoidal at 1000 rpm (open circuit voltage when tested as generator with a drive motor). Calculate (a) the emf constant (V/Rad/s); (b) the torque constant (Nm/A) with optimum position feedback angle; (c) the speed/torque curve, if the resistance per phase is 4 ; (d) the supply frequency at 1000 rpm; (e) curves of input power, output power and efficiency against torque, assuming friction and iron losses are zero; (f) the frequency and speed at which X= L is equal to the resistance R, if the phase inductance is 5 mH; (g) what is the effect of (f) on the speed/torque curve i.e. the effect of L>0 and L>R as speed increases?

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

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