| 摘要 |
<p>PURPOSE:To prevent a brushless motor from damaging by interrupting the drive current when the output frequency of the position detector of the motor becomes higher than the predetermined constant value or when the drive circuit is extraordinarily heated. CONSTITUTION:When a drive circuit 1 and a brushless motor malfunctions so that the motor runs away, the output frequency from a position detector 4a becomes extraordinarily large with the result that the output of a frequency/ voltage converter 5 becomes large, and a positive output is produced from a comparator 7. Since a transistor 8 and a heat sensitive thyristor 10 are conducted by this output, the base of a transistor 11 is grounded, the transistor 11 is interrupted, and the power supply to the drive circuit 1 is interrupted. When the motor is stopped due to some cause or other so that a large current flows, the heated part of the drive circuit 1 is abnormally heated, the thyristor 10 is self- conducted, and the transistor 11 is similarly interrupted to be turned OFF.</p> |
