A brushless direct current (BLDC) motor has high reliability and a long life because it eliminates mechanical friction, and compensates for the defects of a direct-current (DC) motor by removing the brush and commutator. Compared to a DC motor, BLDC motor has the excellent efficiency because there is no voltage drop or friction loss of the brush. However, when the motor is operated for a long time with a high output, the internal motor temperature rises, and the copper-winding temperature increases. The temperature rise of the internal motor affects the resistance of the copper winding and the performance of the permanent magnet. This study investigates the efficiency of a 500 W BLDC motor with a varying air flow rate. The temperature rise and efficiency of the BLDC motor are studied by applying inlet flow rates of 0, 30 and 50 L/min during a 20 min load test. The temperature rise is very high at 0 L/min and the efficiencies are calculated as 81.9%, 82% and 82.7%. This study can be used as a basic study on the optimal air flow rate to the internal motor.
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This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government (MSIP) (2018R1A5A6075959) and the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT).(No. NRF-2019R1A2C1002212).
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Choi, J., Lee, JH., Jung, YG. et al. Enhanced efficiency of the brushless direct current motor by introducing air flow for cooling. Heat Mass Transfer 56, 1825–1831 (2020). https://doi.org/10.1007/s00231-020-02827-8