technical information and definitions

definition for a small transformer

A small transformer with a power less 3 kVA, a primary voltage until 1000 Volt and a secondary voltage less than

100000 Volt is called a small transformer.

conventional transformers

For this type of transformer the core lamination plates are put into the wound bobbins. According to the production

this will be done from one side or alternating. These transformers are also called bobbin- or shell-type-transformers

toroidal transformers

The insulated toroidal core is wound with copper wire directly with a special machine.

primary winding

Must be connected with the line voltage and is marked on the label with PRI.

secondary winding

Is connected with the installation, apparatus or electronics and is marked with SEC on the label.

screen or screen winding

A metallic layer between two windings reduce the transmission of peaks and disturbances. The different screenings are static and magnetic screenings.

transformers with separated windings

This transformer has between primary and secondary a galvanic separation, resisting a normal insulation test.

auto transformer

Is a transformer with only one winding, primary and secondary are connected together.

high voltage transformers

Are transformers with a secondary voltage from 1000 Volts to 100000 Volts.

Electric Current Abroad- voltage and frequencies of foreign countries

Introduction to assist manufacturers, exporters and individuals living or travelling abroad, this publication lists the characteristics of electric current available and the type of attachment plugs used in most countries. The tables indicate the type of current (alternating or direct current), number of phases, frequency (hertz), and voltage, as well as the stability of the frequency and the number of wires to a commercial or residential installation.

This information pertains to domestic and commercial service only. It does not apply to special commercial installations involving relatively high voltage requirements or to industrial installations. For most countries listed here, two nominal voltages are given. The lower voltages are used primarily for lighting and smaller appliances, while the higher voltages are used primarily for air conditioners, heating, and other large appliances. Travellers planning to use or ship appliances abroad should acquaint themselves with the characteristics of the electric supply available in the area in which the appliance is to be used. In some cases, a transformer may be used to correct the voltage.

Here is the download link for the brochure:
www.ita.doc.gov/media/Publications/pdf/current2002FINAL.pdf