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DC2FR > INFO 07.07.02 02:50l 73 Lines 3557 Bytes #999 (0) @ WW
BID : 672DB0GV02H
Read: DB0FHN DG5YMS GUEST
Subj: Again: 110v vs 230v ...
Path: DB0FHN<DB0ZWI<DB0MAB<DB0FBG<DB0CHZ<OK0PKL<DB0MRW<DB0PV<DB0AAB<DB0KFB<
DB0CZ<DB0GV
Sent: 020706/2352z @:DB0GV.#HES.DEU.EU [Frank4t/Mtl OP:DF5FF] DB19c1 $:672DB0GV
From: DC2FR @ DB0GV.#HES.DEU.EU (Wolfgang)
To: INFO @ WW
Hello packeteers worldwide,
Sorry at all - late I discovered the actual discussion about the different
mains voltages 110v vs. 230v ... the reasons, advantages and disadvantages
("INFO" is not so an usual board here in Germany).
This is a very interesting discussion, indeed - but also taking a lot of
time to read all the detailed statements, hi ... !
So, let me add some aspects to this interesting topic.
I have read in some bulletins, 110v 60 Hz would probably be more dangerous
than 230v 50 Hz. This is definitively not true - moreover, it`s absurd.
Simple reason: the higher the voltage - the higher the current - the higher
the danger causing heart fibrillation! AC currents more than 30 mA can cause
heart fibrillation, more than 50 mA mostly cause, and more than 80 - 100 mA
surely cause heart fibrillation! 50 or 60 Hz - this doesn`t matter !
Decreasing effects can only be expected at much higher frequencies.
A scientific examination says, at 400 Hz heart fibrillation treshold
would be 6times higher, at 1000 Hz 14times higher compared with 50 Hz.
This is the reason why high frequency AC currents (in the Kilohertz range)
are significantly less dangerous than power frequencies of 50/60 Hz.
220 volts - 230 volts - 240 volts ...
-------------------------------------
In the "continent countries" of Europe, 220/380 v (220v single phase -
380v three phase) was the dominant mains voltage in the past.
However, in the UK countries (and perhaps Australia ?) 240/415v was usual.
So - the new 230v/400v system is a harmonization compromise, to unite
the different mains voltages in Europe.
Railroad aspects ...
--------------------
In Europe, there are four different systems for electric railroads:
1500 v dc Netherlands, parts of France
3000 v dc Italy, Belgium, Parts of Poland/Czech republic/Russia
15000 v ac 16 2/3 Hz Germany, Austria, Switzerland, Sweden, Norway
25000 v ac 50 Hz France (most parts), Luxemburg, Spain, Portugal, UK,
Greece, parts of Poland / Czech Republic / Russia
The 25 kvac 50 Hz system is now the mostly efficient railroad system -
preferred by countries which started later with railroad electrification.
DC systems have disadvantages due to high current draw in the catenaries,
so thick and heavy overhead cables are needed, just as a lot of feeding
stations along the railroad line.
The German (and also Austrian, Swiss ...) 16 2/3 Hz system is a very old
system founded in the year 1912! Reason was the following: for railroad
traction preferrably used were series commutator motors (like DC motors),
because of their advantages high torque - easily control - good efficiency.
BUT: problems occur when supplying great commutator engines with 50 Hz
AC current due to "transformation voltages", phase shifting and so serious
commutating difficulties. So, a lower frequency was choosen to minimize
these problems. A good compromise was found in 16 2/3 Hz as the common
frequency 50 Hz divided by three.
The system was very successful - so it is used until today, although in
modern locomotives throughout now three phase asynchronous motors are
used instead of commutator engines, driven by power electronics inverters.
So, now the electric system driving the traction motors becomes completely
independent of the mains system ... another aspect to favorize the 50 Hz
(25.000v) system for new railroad electrifications - - -
vy 73 de Wolfgang, DC2FR @ DB0GV, JO40FD, Frankfurt - Germany.
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