Laboratory autotransformers

A laboratory autotransformer or LATR for short is used to smoothly change voltage from almost 0 to the maximum possible value for each particular model.
An autotransformer is practically a voltage regulator. Depending on the number of phases it can be either a single phase or a three phase.
LATR is used domestically when the voltage is low and is unacceptable for household appliances ...