| 摘要 |
Highway crossing gate control circuit in which a permanent magnet motor is controlled to drive up and drive down the gate arm by utilization of a single motor control relay and controller contacts which sense the position of the gate arm. The motor polarity is reversed through utilization of the motor control relay, which is operated by a single up input signal. Provision is included for dynamic breaking on the arm moving downward after an initial drive down mode.
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