The performance of electrical and electronic equipment in railway applications is strict. In Europe this is governed by two international standards. The one most frequently cited in design specifications is the document IEC571, "Electronic Equipment on Rail Vehicles", also known as European Norm EN50155, "Electronic Equipment Used on Rolling Stock Equipment". In U.K., the standard that applies is RIA12, "General Specification for Protection of Traction and Rolling Stock Equipment from Transients and Surges in DC Control Systems", developed by the Railway Industries Association (RIA). While these two standards are similar in most respects, the RIA12 standard also requires a specific surge withstanding capability. Below is the areas covered.

Input Voltage

Interruptions and supply change-over

–  Input voltage interruptions of 10ms shall not cause equipment malfunction (Class S2)
–  The equipment shall operate satisfactorily during a supply break of 30ms at supply change-over (Class S4)

Temperature ranges – EN 50155, IEC 571

Shock and vibrations – EN 50155, IEC 571

Transient and surges

RIA 12 specifies an over voltage surge of 3.5 times the nominal input voltage. Surge duration is specified at 20ms. Source impedance is a low 0.2 . This is a low voltage, high energy surge.

For each of the standard input voltages the maximum input surges are as follows :

                  V_N                     3.5(V_N)
                  ——————————
                  24V                   84V
                  36V                   126V
                  48V                   168V
                  72V                   252V
                  96V                   336V
                  110V                 385V

Meeting EMC Requirement – EN50121-3-2

With a few external passive component, your power system may able to meet conducted emission (per EN55011 class A) and EFT (per EN61000-4-4, 2kV, 5/50 ns, frequency 5kHz)

In case if you need to meet surge (per EN50155, 1.8kV, 5/50µs, source impedance of 100 ) requirement, you can try to add 3 MOVs – one differential and two common-mode at input (not shown).

To meet radiated emission, you can add module shield and putting system within an enclosure.

Vicor Competency : Environmental (EN 50125-1), Shock/vibration (EN 61373) per EN 50155 : 2001

Because of the very special working environmental and battery supply voltage conditions in the railway transportation system, Vicor do provide several input voltage range series DC-DC converter modules to fit for the 24 Vdc, 48 Vdc, 72 Vdc, 96 Vdc & 110 Vdc battery operating systems. Besides, due to the very harsh environment in the railway applications, Vicor did do a series of environmental (per EN 50125-1), shock/vibration (per EN 61373) testing with VI-200 and Maxi DC-DC converter modules in order to demonstrate the compliance of Vicor product from the standard EN 50155. Shock/Vibration test was performed by a third-party qualified lab. NTS. As all DC-DC converter modules are filled in with encapsulant compound, which reinforce shock/vibration resistant that far exceeding EN 50155 (requiring 50m/s²).

The representative power conversion modules were selected from both Maxi/Mini/Micro and VI-200/J00 platforms. Each group was tested as outlined below to demonstrate compliance to EN 50155. Both groups successfully completed the testing with no deterioration in the performance of the modules as demonstrated in the test results. The full test report is documented and available for download from Vicor web site.

Testing requirements:

• all samples must be tested on the standard production ATE tester at Vicor factory before initiating qualification testing;
• Random Vibration Test setup (at NTS):
   –  5 grms total;
   –  50–150Hz @ 0.1725 g²/Hz;
   –  three mutually perpendicular axes;
   –  5 hours/axis

  Mechanical Shock Test setup (at NTS):

   –  Peak acceleration : 5g/2g/1g half-sine waveform;

   –  Duration : 50ms/20ms/10ms;

   –  three mutually perpendicular axes;

   –  6 total shocks

  Temperature/Relative Humidity Test:

   –  Temp : 55°C;

   –  Relative Humidity : 95% RH;

   –  10 hours

  Operating Temperature Test:

   –  85°C for 6 hrs followed by 2 hrs at -40°C

  Electrical Performance Tests with Functional ATE Tester;

  Results : no damage or deterioration

   –  Qualified with test report

Meeting High Energy Surge in 110V Input Railway Applications

RIA12, "General Specification for Protection of Traction and Rolling Stock Equipment from Transients and Surges in DC Control Systems", developed by the Railway Industries Association (RIA) specifies that equipment must withstand a 20ms over-voltage surges 3.5 times greater than the nominal 110V input voltage. That is the surge voltage is 385V for 20ms duration. The source impedance of the over-voltage pulse is 0.2 ohms. That would mean a claming device would need to dissipate up to 3600 J of energy if it is parallel connected to the source and to clamp the surge to 160V, while typical transient suppression devices (TVS) are expected to handle several joules of energy only. What would be the solution so? An active circuit using series pass power device such as a proper MOSFET would be the light of answer.

An example of the active clamp circuit is shown in the figure below. When over-voltage occurs, it triggers D2 to conduct so that the gate voltage of Q1 is then clamped at about D2 voltage. The output voltage equals the clamping voltage minus the gate to source voltage of Q1, thus protecting the downstream DC-DC converter. During normal operating, D2, R3 appear as if they are not there. It is simple here to have Q1 at its fully saturated low drop and low dissipation state using an oscillating signal from U1 to drive a charge pump circuit formed by two 1N4148 diodes and a 470pF capacitor as shown in the diagram. All Vicor DC-DC converters including series of Maxi, Mini, Micro and series of VI-200/J00 would match to this active clamping circuit. Please contact Vicor Applications Engineers for specific component selection. When using Vicor's VI-200/J00 DC-DC converters and in particular the 110V input with "T" part numbers VI-2T_ (or VI-JT_), the gate-out signal from the converter can directly replace the signal from U1, thus a further simplification of the circuit would result.

For a complete description of the circuit, see Vicor's application note "Using Modular DC-DC Converters to Meet European Standards for Railway Applications". The App Note also addresses fast transients and input specifications defined by EN50155 Standard. The circuit shown in the App Note is slightly difference but it is designed for equivalent purpose.

South Korea Newest Express Train – KTX-II
Broadcasting Equipment – The superior performance and reliability of Vicor modules are highly appreciated in the Korean railway industry, where it finds applications in diverse areas such as propulsion control, battery charging, TDCS, SIV and communication systems (PA, Intercom, radio and PID). Shown here is the newest express train (KTX-II) equipped with Vicor modules.

LED / LCD Display Panel for Railways on Board
When using a train look at the new LED/LCD display panel on board. Installed in each compartment this sign carries various kinds of information including destination, next stop, news and weather forecast clearly and in an intelligible form.

Vicor "T" input modules (Vin 66-160VDC, VI-200 and VI-J00 products) are used in this system. With a high reliability (MTBF), low size and weight, and ease of use, the Vicor modules provided the ideal solution.

110V Input DC-DC Converters

Best choice for railway and transportation applications

Vicor offers the widest choices of 110Vin DC-DC converter in the industry

VI-200/J00 T input series DC-DC converters is design for train application. Featured with 66-160V input. These 110V input modules offer output options from 1 to 95V with maximum power up to 200W, 3000V rms isolation.

New 110V Maxi, Mini & Micro series featured with a wide input range from 66 to 154V, these modules offering includes five different environmental grades with eight standard output voltages (3.3, 5, 12, 15, 24, 28, 36, 48 V) in combination with six different pin options and three base plate styles, with output power ranging from 50W up to 400W & output voltage is 330mV - 52.8V. Meet EN50155 vibration/shock requirement.

These DC-DC converter modules use advanced power processing, control and packaging technologies to provide the performance, flexibility, reliability and cost effectiveness of the mature power component. High frequency ZCS/ZVS switching topology provides high power density with low noise and high efficiency. These modules are encapsulated circuitry for shock and vibration, rugged & reliable for the railway/transportation system applications development.

Performance specifications include a wide input voltage range in accordance with EN50155 as well as efficiencies ranging up to 90% for the higher output voltages. Customer can also configure any input, output and mechanical combination using Vicor's patented intelligent design system – PowerBench™, and verify them in real time.

Furthermore, Vicor has more modules comply with EN50155 input specification.

Vicor Railway Brochure -

Vicor offers component power solutions that are ideally for the rail industry. Nowadays, our products are used in almost every Asian and European rail network.

Sudoku from Vicor ?

Solve this Sudoku puzzle and use the letters to find the hidden word.

Please email your answer with your name, mailing address & contact phone no. to vicorhk@vicr.com no later than 1st January, 2008. All entrants submitting the correct answer will be entered into a prize draw to win one of Vicor 512MB USB *.

How to play: A Sudoku puzzle consists of a grid with nine cells across and nine cells down. This grid is subdivided into nine blocks with 3 x 3 cells in each. The object of the puzzle is to fill the game grid so that each row, column and 3 x 3 block contains the numbers 1 to 9 exactly once. The numbers can appear in any order and diagonals are not considered.

In a Sudoku puzzle there is only one possible solution, and this must be able to be found logically! Since the numbers 1-9 can only appear once in each row, column and 3 x 3 block, possible numbers for the empty cell can be excluded dependent on other numbers of this value that have been provided or already solved.

Good Luck!

* The Quiz does NOT open to Vicor employees or distributors.

Congratulations to the Winners of Quiz8 listed below:

1. Australia, Mawson Lakes – Tom Mrozinski
2. India, Bangalore – Ajay B More
3. India, Channai – V.Selvakumar
4. India, Channai – Vinoth Kumar. D
5. India, Indore – Dhananjoy Deokar
6. India, Hyderabad – K.V. Ramana Rao
7. India, Secundrabad – Vinay.D

For those who didn't receive the gift yet, please kindly email to us at vicorhk@vicr.com. Thank you!