the use of autotransformers is strictly prohibited.
Autotransformer A set of coils, which have a tap, can not achieve isolation. Or two sets of coils are attached.
Double-winding type safety isolation transformer load side and the power supply side is not electrically connected, is safe, and autotransformer primary shared a winding, it has a direct electrical connection with the power supply, unsafe.
The double-winding type safety isolating transformer has two windings which are input (primary) windings and output (secondary) windings, and the two windings are insulated from each other, only by magnetic connection, that is, secondary Winding and the earth does not constitute a loop, if the use of additional insulation appliances, you should use a safe isolation transformer.
And since the lotus transformer all of its winding are connected, by sliding the position of the contact to change the size of the voltage. Therefore, the autotransformer primary winding (power circuit) and the secondary winding (power supply circuit) is not only between the magnetic connection, as well as the direct connection of the circuit. It and the earth constitute a loop, so it can not be used as a safe voltage power supply.
Therefore, the safety regulations: lighting transformers must use double-winding type safety isolation transformer, prohibit the use of autotransformers.
