The Automatic Voltage Regulator – AVR:
Guide and Comparison
The Operation, Application and Comparison of Automatic Voltages Regulators in AC Power Applications
6.1 Tap Changing Voltage Regulator Operation
Simply said, when a transformer has an equal number of winding turns on the primary (input) and secondary (output), the input and output voltage should be equal. By adding or subtracting the number of turns on the secondary, the output voltage can be changed – up or down, respectively. Rather than physically changing the number of turns, the turns ratio can be altered by changing the location of the physical connection to the secondary. Transformers often have multiple locations (known as “taps”) for connection to the secondary to adjust the output voltage.
The mechanical tap changing voltage regulator utilizes contactors or brushes along with some type of motorized drive system to change the taps on the secondary of the transformer. A simplified diagram is shown at the right. The controller monitors the output voltage and operates the drive system to change taps until the output voltage is within the proper range. There are many variations on this type of arrangement.
Quick Links
1 The AC Automatic Voltage Regulator
2 Automatic Voltage Regulators and Power Conditioners
3 The Need for Automatic Voltage Regulation
4 Automatic Voltage Regulator Function
5 The Ferroresonant Transformer (Type) Voltage Regulator
6 The Mechanical (Type) Voltage Regulator
7 The Electronic (Type) Voltage Regulator
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