The auto transformer is a device used for the following purposes:
1) attach the device to the electric networks of alternating current with voltage (127, 220, 380V);
2) to repair voltage electric networks;
3) the voltage control of the main transformer in x-ray machines or input voltage physiotherapy and other appliances;
4) electric power auxiliary circuits of devices.
Autotransformer is an integral part of most x-ray, physiotherapy and other devices and placed usually at the remote control unit. The use of autotransformer necessarily also when using electrical devices and electrical appliances (boilers, sterilizers, drying ovens, refrigerators and other), operating voltage which does not correspond to the mains.