Autotransformer voltage regulator

Autotransformer "ARN-250" from the beginning of 1957 produced the Moscow transformer plant named after Kuibyshev. Autotransformer type "ARN-250" (Autotransformer Voltage Regulator, with a load capacity of up to 250 watts) is designed to power TVs, radios and other radio or electrical equipment when the voltage in the electrical network is lowered by a voltage of 220 volts regulated by a voltmeter. In the 50s ... 80s, in the evening, the voltage in the city power grids dropped to 170, and in the district ones to 140 or even lower due to the inclusion of lighting and televisions by the population. And in winter, the values ​​reached even lower values. In the mornings, by the way, on the contrary, the voltage could reach 235 V or more, which could be lowered to 220 V. A convenient and inconvenient thing, you constantly had to monitor the voltmeter and turn the regulator every 20 ... 30 minutes.