RS PRO 250VA Enclosed Autotransformer, 220 V ac, 230 V ac, 240 V ac Primary, 115V ac Secondary

Autowound transformers for step-up or step-down of mains voltages at 50/60Hz.

Compact construction
Full varnish impregnation
Fully shrouded
Four-hole fixing for permanent installation
Terminal blocks with protective covers (except 50VA which has leads)
100% electrical and flash tested (2kV winding to core)
Tested in accordance with EN61558

These units do NOT provide isolation from the mains.

RS PRO's enclosed autotransformer provides an efficient way to reduce power supply voltage. Its primary rated voltage is 220 V AC, 230 V AC or 240 V AC, and the secondary voltage is 115 V AC. This means you can use it to operate US equipment at higher European voltages.


The autotransformer's four-hole fixings and compact construction mean it's easy to install in a variety of locations. It's fully shrouded to prevent electrical interference and has a varnish-impregnated coil for increased dielectric strength. Its terminal blocks are equipped with a protective cover, and the device has undergone extensive electrical and flash testing to ensure safe high-voltage use.


This autotransformer is suitable for many applications, including induction motor starting and transmission line voltage regulation. It does not provide mains isolation.