20Amp Variable Auto Transformer AC Voltage Regulator Power Supply

This variable transformer is the perfect speed controller. The speed is infinitely variable, and because a transformer doesn't chop up the AC waveform like electronic speed controllers do, there's no noise, humming, etc.
If you're planning on using this as an "industrial" or bench-top supply with heavy loads, I'd recommend examining the brushes and adjusting the spring pressure on the windings. This can improve performance by reducing brush-contact sparking. Otherwise, this device is ready to work right out of the box.

There are a lot of common uses and practical applications for variacs. As we mentioned earlier, theyre more portable and more cost-effective than regular AC power supplies, which pretty much makes them a top pick for short-term projects and casual hobbies. variable autotransformercan be used to gradually revive previously dormant electronic equipment. They can also be used to regulate servo motors and control the temperature of ovens and heaters.
Voltage adjustment, when used with thermostatic control, provides more uniform heating.
You can also use variacs to simulate various voltage and line conditions for experiments, or power electrical equipment designed for voltage that isnt the typical 120V or 240V supplied domestically.
Here are some other applications:
Regulating voltage
Controlling specified input voltage to rectifier elements to generate variable DC voltages from an AC source
Operating electrical equipmenttypically motorsat the correct or optimal voltage even with subnormal or higher-than-normal supply
Varying step-transformer output voltage by control of input voltage Starting synchronous or induction motors in order to provide 50%-60% of the total voltage to the motor stator during start-up.
Correcting voltage in subnormal or over-voltage supplies on 1-phase, 2-phase, or 3-phase circuits
Compensating for voltage drops by giving small boosts to the distribution of a cable Controlling AC motors and DC motors operation rectified AC circuits Powering fans and other motors with low starting torque
Controlling the brightness/
Extending lamp life by operating it below rated voltage
Calibrating electrical equipment and controls
Compensating for appreciable voltage drops at the end of lines where distances run too long