Frequency inverter and its triumphal procession in electrical engineering in industrial plants and machines, Fittnessgeraten and even household appliances the so-called frequency inverters used today for speed control of drives. This greatly simplified description does not to the better understanding of all, largely on terms and physics. Mostly Gleichstrommotore is used for the speed control in industrial machinery, the advantages of the Drehstrommmotors and the miniaturization of electronics have led that speed control is carried out mainly with three-phase asynchronous motors and frequency inverters. The benefits are robust and largely maintenance-free better power to weight ratio among others cheaper than DC motors. The biggest advantage is that nearly every commercially available three-phase motor with frequency inverter in the speed can be controlled. Frequency inverters are used so for speed control of three-phase motors.
Because the speed of the three-phase motor with changing frequency changes,. It reached a speed control by a voltage applied to the motor with regulated frequency. Thus, the speed is controlled by the frequency applied to the motor. The tension is here adapted to the respective speed. A variable speed drive can be realized with a frequency converter and a three-phase motor, so today with low cost. Through the programming of the frequency converter brakes, speed, torque can be designed specifically to the application at another time.
The programming can be performed mostly for simple applications on the device itself. Often the manufacturer offer simple programmers or programming is done directly from the PC or notebook. Often, in today’s modern FU’s, the behavior of the drive can be changed and adjusted with several hundred adjustable parameters. That must be made by an expert, because damage to the drive on the machine, even personal injury can be caused by incorrect programming. Setting the speed is done with simpler applications usually via a potentiometer. The problems are a major drawback of the frequency inverter. There will be repercussions on the supply network (pollution), as well as to the electromagnetic radiation. Remedies must be shielded cables and filters used.However, some manufacturers include the necessary filters right into the device. The regulations and the operating instructions of the device type information. Frequency converters are usually for 1-phase supply voltage in the power up to 1, 5kW offered.Services 1, 5kW are 3Phasen devices used. The prices for such electronic products are declining rapidly. Simple frequency inverters in the line class 0, 37kW or less are available already for a little over 100. This explains why frequency inverters are used very often, and the DC drives have almost completely displaced.