To provide a small-size and thinner railway crossing gate which does not require a clutch comprising a brushless motor given a torque limit character istic through the current control.
A drive circuit of brushless motor 10 with a brake comprised in the railway crossing gate is configured with a power transistor 1, a rotating signal logic 2, motor rotating position detecting circuit 3, a rotating speed drop detecting circuit 4, an ON/OFF control circuit 5, PWM control circuit 6, a current (torque) command 7, a current detecting circuit 8, a motor overheat detecting circuit 9, and a power supply 13. The torque limit characteristic can be given by detecting an output current signal of the power transistor 1 with the current detecting circuit 8, and inputting this signal to the PWM control circuit 6 via an adder and a subtractor together with a current (torque) command 7; controlling the drive pulse from the rotating signal logic 2 by way of the obtained PWM pulse; outputting a motor drive current corresponding to the current command from the power transistor 1 by controlling ON and OFF the motor drive current outputted from the power transistor 1; and outputting a torque proportional to the motor drive current from the brushless motor 10.
KATAYAMA RYUJI
KAJIKI TOMOHIKO
TOKUSHU DENSO KK
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