ATL Transformers Academy


ATL design and deploy leading magnetics to the rail network and its principle contractors. We offer the highest specifications on the market while maintaining competitive pricing against alternative legacy technology. Our magnetics are approved for use by Network rail, Crossrail, London underground and are widely used to support Designers, Route asset manager, maintainers & Installers. As the preffered solution in rail ATL’s New generation of magnetics, eco-rail® is raising the bar on quality and performance, delivering unprecedented levels of weight/size reduction, ergonomics, Carbon reduction and safety.

ATL Academy Transformer Safety Standards

Transformer Safety Standards


Transformer Standards EN61558-1

The old VDE 0550 and VDE 0551 transformer standards do not exist anymore. The previous EN 60742 (VDE 0551) transformer standards is outdated now also.
The up-to-date standards for transformers are now BS EN 61558 IEC 61558 (VDE 0570). Part 1 of the standard explains general requirements and tests. Part 2 lists special transformer types like safety isolating transformers (part 2-6) or SMPS transformers (part2-17) a separate standard, which still has a connection to part 1, for general requirements.


European standards for transformers


EN 61558-1

Safety of transformers

(VDE 0570 Teil 1)

General requirements and tests



EN 61558-2-4

Particular requirements on isolating transformers

(VDE 0570 Teil 2-4)

for general use



EN 61558-2-6

Particular requirements on safety isolating transformers

(VDE 0570 Teil 2-6)

for general use



EN 61558-2-17

Particular requirements on transformers

(VDE 0570 Teil 2-17)

for switch mode power supplies


Other European standards


DIN EN 50020

Electrical apparatus for potentially explosive atmospheres

VDE 0170/0171



Safety of electrically energized office machines

VDE 0806


DIN IEC 65 EN 60065

Safety requirements on mains operated electronic and related apparatus for

VDE 0860

household and similar general use


Safety of medical equipment

VDE 0750


DIN EN 61010

Safety requirements on electrical equipment for measurement, control and

VDE 0411

laboratory use

DIN EN 60950

Safety of information technology equipment including office machines

VDE 0805


UL (Underwriter Laboratory, USA) standard


UL 506

Special Transformers

UL 544

Medical and  Dental Equipment

UL 131

Direct Plug-in  Transformers

UL 1585

Class 2 and  3 Transformers


ATL Transformers can produce transformers with UL and or CSA (Canadian standards) approved materials and on demand will send a chart with the materials used.

Transformer Temperature & Insulation

ATL Transformer Design

Our transformers are designed in a way that does not allow impermissible temperatures. The insulating materials have at least class E conforming to IEC 85, mostly class F (155 deg C) & class H (180 deg C) and on request even higher temperature classes. For the technical calculation, the temperature is calculated at 1,06 times the primary voltage in rated operation and in short-circuit case.

Read More About Transformer Temperature & Insulation

Transformer Screening

Definitions of ATL screens

Safety isolating earth screen

A metallic material (typically copper foil) between the primary and secondary windings offering isolation to ground between the two windings sometimes referred to as: Separation of dangerous active components by use of a conductive shield, which is located between the two parts and is connected to an external earth terminal.

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Transformer Voltages

Low voltage

Low voltages are rated voltages that are not higher than 1000 V AC.

High voltage

High voltage is defined as a voltage, that is higher than a low voltage of 1000 V. The maximum we are able to produce at the moment is at 50 kV AC.

The AC high voltage output has the following special characteristics: One terminal is connected to earth (minus pole, green/yellow connector) and the other terminal is connected to the high voltage side (plus pole or “hot side”).

Current is calculated with the power I = P/U and is usually given in [mA].

The frequency is at 50 Hz sinusoidal. For special fields of application, frequencies can be higher. We already built transformers with 20 kV and 1000 Hz.

The insulation test primary – secondary is done with 120% of the high voltage value..

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Line Reactors

ATL Transformers Line Reactors conform to EN 61558, EN 5008-1 and -2, EN 50082-1 and -2

Read More About Line Reactors

Transformer Frequency
Effect of frequency
Transformer universal EMF equation

If the flux in the core is purely sinusoidal, the relationship for either winding between its rmsvoltage Erms of the winding , and the supply frequency f, number of turns N, core cross-sectional area a and peak magnetic flux densityB is given by the universal EMF equation.

Read More About Transformer Frequency


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