摘要 |
In a roller with a built-in motor, which is powered by a brushless motor and stopped by an electromagnetic brake, when an electric current is supplied to the brushless motor, an electric current is supplied at a certain voltage to the electromagnetic coil to release the electromagnetic brake. The rpm of the brushless motor is detected; and when it reaches a certain predetermined level, the supply of the electric current to the electromagnetic coil is turned off and on in a short period of time, thus maintaining the released condition of the electromagnetic brake. By turning off and on the supply of the electric current to the electromagnetic coil, the average voltage can be maintained low, and the heat generation can be reduced.
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