The motor torque is measured to verify the efficiency of SMC
BLDC motor. A N-T curve is chosen for measurement because
it can estimate the ability of BLDC motor through N-T curve
characteristic. The measured N-T curve is the same as shown in
Fig. 7 and Fig. 8. In Fig. 7 and Fig. 8, A1 is input current; Wn1 is
input; Hp is output; Eff is efficiency; RPM is rotations of motor
measured up to 3000[rpm] and 3600[rpm]. According to each
rising torque value, a stability time is necessary. So the curve
gets an inflection point. Operating range of load in the
compressor is 4 [kg