Basically, a voltage stabilizer is made of a buck/boost transformer, a voltage regulator, and electronic control. Based on a microprocessor that samples at high frequency the output voltage, the control system drives the regulator gearmotor. By doing so, the regulator rollers change their position, and therefore the voltage is drawn and supplied to the buck/boost transformer primary winding. Being the secondary voltage of the buck/boost transformer in phase or in opposition to the supply, the voltage is drawn from the regulator is added or subtracted to the mains voltage, thus compensating its variations.
1. Buck/boost transformer
Often referred to as a ‘booster’ transformer, it is a standard dry-type transformer with the secondary winding connected in series to the mains and the primary winding supplied by the voltage stabilizer.
2. Voltage regulator
Basically, it is an autotransformer with a continuously variable transformer ratio. The voltage intake varies depending on the position of the rolling contacts; therefore the voltage supplied to the booster transformer primary winding also varies. Being the voltage across the regulator contacts (and consequently that on the secondary winding of the booster transformer) either in-phase or in opposition to the supply voltage, it is then added or subtracted to the supply voltage, thus compensating its variations.
3. Auxiliary circuit with microprocessor
The DSP (Digital Signal Processor) microprocessor-based control circuit (specifically designed for drives with totally digitalized signal) compares the output voltage value to the reference one sampling it 2000 times per second. When an anomaly is detected, the control drives the voltage regulator gearmotor. By doing so, the regulator rollers change their position thus varying the voltage drawn and supplied to the buck/boost transformer primary winding. The input voltage variation is therefore automatically compensated. The control system and the construction methods of the machine ensure that the output accuracy is ± 0.5%.
Voltage stabilizer main components