Voltage-controlled systems

Just as for the primary-voltage control system, the air-gap power at slip s divides between mechanical power and rotor-circuit power in the wound-rotor drive. Except... 

Because of their application in voltage control systems, it is worthwhile to discuss the operation of variable voltage transformers in greater detail A number of conventional transformers can have—to a limited... 

Voltage-controlled systems rely on the tissue resistance to limit the current. Due to the buildup of voltage across the capacitor and electrode interface, the remaining voltage drop across the tissue decreases over the pulse duration. This is reflected in... 

It is easy to notice, that the protection against a short-circuit failure in the X-ray tube circuit implements due to the "soft" outer characteristic of the apparatus main circuit. The overvoltage protection at emergencies in the control system happens due to the redistribution of the magnetie flow, created by power winding I, between the 3,6 control yokes. Therefore the voltage on the X-ray apparatus anode drops approximately two times. 

Engbarg. K. and Ivner.. S.. Static VAr Systems for Voltage Control During Steady State and Transient Conditions. May 1981. Reach vePowerCompen.sation Department, Sweden. May (1981). 

Electronic control A control system operating on low voltage, making use of solid-state components to amplify input signals from which the control functions are performed. 

Both electronic and microcomputer-based controls require information about the state of the controlled system. Sensors convert different physical variables into an electric signal that is conditioned and typically converted to a digital signal to be used in microcontrollers. The trend in the construction techniques of modern sensors is the use of silicon microstrnctures because of the good performance and the low cost of this type of device. In the energy control scope the main quantities to be measured are the temperature, pressure, flow, light intensity, humidity (RH), and the electric quantities of voltage and current. 

Speed adjuslmeiU from base speed downward is obtained by armature voltage control. The armalure current and torque in this range is limited by the thyristor ratings or motor temperature rise. Control above base speed at constant horsepower is obtained by field weakening. An example system is shown in Figure. 3-17a. In this... 

The tip is first brought near to the sample via a coarse Z positioner, such as a controlled approach piezo-electric motor. This provides a 10 A step size and so is capable of very precise and controlled movement. As soon as a tunnelling current is detected, the tip is stopped and the fine control system is operated. Thus the lip is mounted on the end of a hollow, cylindrical piezo crystal, a tube scanner (a piezo-electric crystal can be made to deform under the influence of a voltage applied across it). The tube scanner has four strip electrodes on the outside, providing movement in the x and y directions (lateral movement), and one electrode covering the whole of the inside. A... 

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