| 摘要 |
<p>A solid-state electronic control system for an electric motor which drives a pipe bending machine. A machine operator's hand switch acts through a logic system to cause the motor to run in either direction, and negates control conflicts. The logic system controls an SCR bridge system to select the direction of D.C. energization of the motor for forward or reverse drive. This bridge system is supplied from A.C. mains through a bridge rectifier comprising three diodes and one SCR. When motor drive is called for, this SCR is made conducting to provide full-wave rectification. When motor drive is terminated, this SCR is turned off so that the rectifier becomes half-wave, which facilitates turn-off of the motor reversing SCR's. A dynamic brake for the motor is turned on by a triac when motor energization is shut off.</p> |
