| 摘要 |
The proposed control system for the ultrasonic transducer of a device for ultrasonic vibroimpact treatment of metals contains an ultrasonic vibration generator, a power amplifier with an output transformer, and a piezoelectric transducer with impact elements, which are connected in series, a unit for adjusting the generator frequency with a circuit for starting this unit, a feedback current transformer with the primary winding connected in serieswith the secondary winding of the output transformer, and additionally, a current feedback signal former, a normally open switch, and a normally closed switch. The secondary winding of the current transformer is an element of a resonance circuit. The switches are connected in series to each other and the output of the unit for adjusting the generator frequency. The secondary winding of the current transformer is connected to the input of the feedback signal former, the control input of the normally open switch via a threshold element, and the control input of the normally closed switch via an inverter. The Q-factor of the resonance circuit containing the secondary winding of the current transformer is less than the Q-factor of the unloaded piezoelectric transducer but exceeds the Q-factor of the transducer under maximal operating load. The circuit for starting the unit for adjusting the generator frequency contains a switch in the manual start circuit and the sensor of contact pressure between the impact elements of the transducer, which are connected in parallel.
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