Photoblog

When you are lucky enough to have the insight into the interior technical details of a German ICE 2 high-speed railcar, you may realize that the main transformer has 7 output windings. Next to 4 windings with a 1 MVA output for the 4 inverter drives, you will find 3 windings for ancillary supplies, among them one for the carriage heating with an output rating of 500 kW!

But also without such opportunities, you only need to look around at the railway stations, and you will find quite a number of connection points for train pre-heating. Since most passenger trains in Germany are either operated electrically or they come as railcars with integrated diesel engines, these connection points are mostly no longer in use today (as the label tells you here for example). But note that the voltage ratings are 1500 V, 2000 V or 3000 V! This is not done for fun but because the heating of (especially old) trains guzzles tremendous lots of energy. This remains to be included into considerations about how to make railway transportation even more energy efficient, which despite all it already is, but there are still significant potentials left.

Here you see a duplicate duplication … but this you already know. What is new is that now the 2 lamps on the left give a bright white light, and the two on the right are dim and yellowish, opposed to the previous photo! While nothing much was changed – the photo was only taken a moment later.

Several shots showed that it is just a matter of luck whether the left or the right lamps are clear, or whether they appear more or less equal. Rather, it is a question of the point of the phase when the respective lamp is being photographed.

Morals: When taking photos of fluorescent lamps in operation, make sure your shutter time lasts at least one period of the mains frequency! Then these effects do not turn up. But obviously the colour of the lamps changes over a period.

Here you see a duplicate duplication in so far as the advantageous tandem operation mode of 2 fluorescent lamps is combined with a lead-lag compensation of 2 such pairs, which is also quite an advantageous thing to do if done adequately. But when you want to take a photo to demonstrate the difference between the leading and the lagging pair, then you end up with a surprise: Does the phase angle take influence on the colour rendering of the lamps?

At the 2008 Light & Building fair in Frankfurt a company producing electronic starters for fluorescent lamps with magnetic ballasts exhibited a new demo panel. The panel compares 6 systems:

1. An uncompensated 58 W fluorescent lamp with a class B1 magnetic ballast.
2. A 58 W fluorescent lamp with a class B1 magnetic ballast and serial compensation (forming a lead-lag compensated pair with the former), whereas the capacitance can be selected to match the official rating of 5.2 µF or to be reduced to 4.6 µF, at which the actual current value will more or less equal that of the uncompensated lamp.
3. A 58 W fluorescent lamp with a class B1 magnetic ballast and parallel compensation (7.0 µF).
4. A 58 W fluorescent lamp with a class B1 magnetic ballast but which is rated 240 V instead of 230 V.
5. A 58 W fluorescent lamp with a class A2 electronic ballast.
6. A 58 W fluorescent lamp with a class B1 magnetic ballast and a Voltage Optimizer “EOS” 900 VA 230 V/195 V by www.ipsi.dk.

Each system is equipped with a multimeter panel displaying the incoming voltage, active power and reactive power. All of them are fed from a common variable transformer, except No. 6, which is connected directly to the supply.

A seventh meter displays the overall values, so as to display the good compensation performance of the lead-lag circuit.

It can also be seen that when the voltage is set to a level at which the input power to the system No. 5 with the electronic ballast is equal to that of any “normal” B1 configuration, which is the case at around 215 V, there is no visible difference in light output. This raises doubts about the possible energy efficiency improvements with electronic ballasts. At least the potential seems to be rather limited against the best commercially available magnetic ballasts.

On top of this, switching system No. 2 accordingly shows that the electronic starters used in the panel reliably start the lamp even if the voltage drops to 190 V and at the same time the serial compensation capacitance is reduced below the official rating.

Elektrizitätswerk Dietlikon are the first regional utility known to use 5-core underground cables for the new-built, extension and repair sectors. The cable has 3 phase conductors made of aluminium, 1 neutral conductor of equal cross section but made of copper for coping with the potential harmonic currents and a copper screen used as PE conductor. This was the best compromise that could be achieved in negotiations with the cable maker who first wanted to use only aluminium.

New reinforcement of new building insulation (as implemented by EU countries in the frame of the EPB directive) will in the long term change completely the heating technologies in future houses. Central heating systems have already become too expensive in many cases compared to the simple electrical heating that might be the standard in very highly insulated houses. For the other buildings, heat pumps and combined heat and power generation will gradually replace the CH boiler technology.

Courtesy Energy Pictures Online

There is active fluorescent lighting and apparent fluorescent lighting. Often the so-called Linestra lamps are confused with fluorescent lighting tubes by laymen - and not only by laymen - because of their tubular design. Albeit, a Linestra lamp is an incandescent lamp, and one with a very poor efficiency on top of this! The efficacy is only half as good as that of a general purpose incandescent light bulb of comparable power rating. Linestra lamps are one of the few electric devices that actually do fall into the lowest category "G" of the EU's energy efficiency labelling scheme. 

This is while the magnetic stray field of a low voltage distribution panel is right in the middle between the two. But after all, the distance is very short in this photo, the enclosure opened and the meter so close to the conductors as otherwise would not be possible to approach the conductors at all if the cubicle were closed. Morals: Magnetic stray fields are often over-estimated.

…while outside the station the value already drops to less than 1% of that value, so no excession of any environmental limits!

Who's afraid of magnetic fields? And if so, who are the culprits? Probably those whose basic principle of working is magnetic fields – or rather not that much? This transformer has a magnetic stray flux of 37.8µT when measured right on top of the cover, where people should not walk anyway for a number of reasons ...

Normally when an incandescent light bulb dies the filament blows. This may be the symptom or the cause, but it is always the same appearance.

Always?

No.

The light from this bulb did not go instantaneously with a bang or flash, but faded away over a few seconds, as if the lamp were dimmed down. The autopsy revealed that the filament was still in order. Rather, there was a blackening to be seen in the middle of the glass tube which holds the (obviously interrupted) wires contacting the filament. Contacting these wires externally showed that the filament was still operable.

Courtesy de - Der Elektro- und Gebäudetechniker hereby a series of pictures about electrical safety hazards observed in buildings. Some even include public places such as restaurants or railway stations.

One of Christianity's virtues is hospitality. The chief of the Catholic Church even invites lightning to come right in through the window!

Detail of last week's picture, to make the story clear.

... will inform him when lightning strikes St. Peter's Cathedral, goes down the (stranded) down conductor past the window, flashes over to the bell cable and rings the bell!

Well, if you are left in a non-smoking room and want to smoke without risk of setting off the alarm, this is what you can, but should not, do!

…when DC and AC powered railway lines are paralleled, such as here in Berlin Spandau station (and all across Berlin). It came as a great surprise, even to one of the so-called harmonics gurus, when he was measuring the no-load power intake of a 200 VA toroidal core transformer and turned on a hot air blower to half power on the nearest socket.

Suddenly, the no-load power leapt up from 1.8 W to 38 W! In the long run, this would have charred the transformer even without any load. The no-load current even rose from 9.2 mA to 1.26 A! What had happened? The power of such blowers and hair dryers used to be halved by simply inserting a diode into the current path. This caused an asymmetric voltage drop, i. e. a DC component, in the mains of, say, 0.5 V. Now, if the transformer's no-load current, which already brings the core close to magnetic saturation, is only 10 mA and the ohmic resistance of the primary winding is some 20 Ω, then the 0.5 V DC component of the line voltage will already drive a direct current of 25 mA in the primary winding and thereby fully saturate the core.

Therefore, this approach is now in effect prohibited by the latest release of the EN 61000-3-2, limiting the second harmonic to 1.05 A, but which applies to domestic appliances and not to locomotives. One may wonder whether the same could not happen to the transformers in the AC locomotives when the return currents from the DC and AC railways share one rail and cause a DC voltage drop along the rail of the AC driven train.

... will you find HV pylons on the middle of the road!

... does not really contribute to a good image of East European electrical industry in the West.