kinsman@ektools.UUCP (Andrew A. Kinsman) (12/13/89)
I was wondering if anybody on the net had any historical information on why Europe is 50Hz? Did the standards for each country get set at the same time? Was it political, to keep our products from interfering in their market place? Thanks for any information. Andrew Kinsman rutgers!rochester!kodak!ektools!kinsman Eastman Kodak Co., Rochester, N.Y. "Little Yellow Box Factory"
sde@larry.sal.wisc.edu (Scott Ellington) (12/13/89)
I don't know about the history or politics of the choice of 50 Hz for power distribution in Europe, but it may have been a simple engineering trade-off. At 50 Hz, transmission losses are a little lower that at 60 Hz, but motors and transformers are larger and more expensive.
kawaguch@ohe-sun3.usc.edu (Atsushi Kawaguchi) (12/13/89)
In article <2332@ektools.UUCP> kinsman@ektools.UUCP (Andrew A. Kinsman) writes: > > I was wondering if anybody on the net had any historical > information on why Europe is 50Hz? On a related matter, in Japan, everything east/north of Mt. Fuji, including Tokyo runs on 100v AC/50hz power line, and everywhere west/south, including Osaka, runs 100v AC/60hz power line. The reason was, power company in Tokyo side didn't talk about getting a generator with Osaka side, and they got it from European country. Likewise, Osaka side bought a generator from U.S. without consulting anyone. Many appliances sold in Japan which needs to set frequency has a small switch to select frequency, but some machines like old microwave, must be taken to ship to flip a switch. U U SSSS CCCC Atsushi Jun Kawaguchi U US C INTERNET: kawaguch@girtab.usc.edu U U SSS C U U SC UUU SSSS CCCC
grr@cbmvax.commodore.com (George Robbins) (12/13/89)
In article <787@larry.sal.wisc.edu> sde@larry.sal.wisc.edu.UUCP (Scott Ellington) writes: > I don't know about the history or politics of the choice of 50 Hz for > power distribution in Europe, but it may have been a simple engineering > trade-off. At 50 Hz, transmission losses are a little lower that at > 60 Hz, but motors and transformers are larger and more expensive. Actually, If I remember all this sillyness, for power equipment including motors and transformers lower frequencies are still cheaper because AC core losses (eddy current, hysteresis, etc), are lower allowing less complicated construction (thicker/few lamination) and less cooling. Some of the major U.S. railroad electrification projects used 25 Hz for just this reason and were still using 25 Hz up to a few years ago, though the economies of custom power generation/converison had vanished with the advent of major power nets. Don't ask me why they didn't use 30 Hz... -- George Robbins - now working for, uucp: {uunet|pyramid|rutgers}!cbmvax!grr but no way officially representing arpa: cbmvax!grr@uunet.uu.net Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)
wbrown@beva.bev.lbl.gov (Bill Brown) (12/14/89)
In article <8973@cbmvax.commodore.com> grr@cbmvax.commodore.com (George Robbins) writes: >Actually, If I remember all this sillyness, for power equipment including >motors and transformers lower frequencies are still cheaper because AC core >losses (eddy current, hysteresis, etc), are lower allowing less complicated >construction (thicker/few lamination) and less cooling. This allowed the traction motors to be somewhat smaller, as less volume was used up as insulation between the stator laminations. For various reasons, series-wound motors are generally more satisfactory as traction motors, altho I seem to recall that both G.E. and E.M.D. are experimenting with using synchronous motors (actually a form of stepping motor) driven by a solid state frequency generator. This will remove the maintenance problems associated with commutators. > >Some of the major U.S. railroad electrification projects used 25 Hz for >just this reason and were still using 25 Hz up to a few years ago, though >the economies of custom power generation/converison had vanished with the >advent of major power nets. The use of higher frequency power supply was not practical until good high-power rectifiers became available. Several locomotives using mecury ignitron rectifiers were built in the late 40's-early 50's, and silicon rectifiers are now used. > >Don't ask me why they didn't use 30 Hz... One railroad, the Visalia (sp?) Electric in California used 15 Hz electrification; I believe that it was also used in Europe. The frequency is a trade-off. In distributing power to locomotives, it is desirable to use the highest voltage possible in order to minimize power losses. There is (was?) no easy way to "step up/step down" D.C. When A.C. is used, it was normally transmitted at high voltage (11 KV being the most common). However, as the frequency goes down, the ammount iron required for the locomotive-mounted transformer goes up. There are practical limits to the operating voltage for a series-wound motor; it gets hard to build one to run on much more than a thousand volts or so, especially given the cruddy environment in traction service. The early engineers had to make some interesting trade-offs to come up with the system that eventually evolved. Things are still changing. -bill wlbrown@lbl.gov Disclaimer: These opinions are my own and have nothing to do with the official policy or management of L.B.L, who probably couldn't care less about employees who play with trains.
tomb@hplsla.HP.COM (Tom Bruhns) (12/14/89)
sde@larry.sal.wisc.edu (Scott Ellington) writes: >I don't know about the history or politics of the choice of 50 Hz for >power distribution in Europe, but it may have been a simple engineering >trade-off. At 50 Hz, transmission losses are a little lower that at >60 Hz, but motors and transformers are larger and more expensive. >---------- An Old-Timer once told me, when I was much younger, of the days when at least portions of the US were on 25 Hz power. Can you say, "Holy Flickering Incandescents, Batman!" He worked at Hoover (Boulder) Dam, where the local power continued to be 25 Hz for quite a time after the grid was converted to 60 Hz. He said it was lots of fun building a power supply for his ham transmitter that didn't end up with a lot of ripple.
jgd@rsiatl.UUCP (John G. De Armond) (12/14/89)
In article <8973@cbmvax.commodore.com> grr@cbmvax.commodore.com (George Robbins) writes: >Actually, If I remember all this sillyness, for power equipment including >motors and transformers lower frequencies are still cheaper because AC core >losses (eddy current, hysteresis, etc), are lower allowing less complicated >construction (thicker/few lamination) and less cooling. > >Some of the major U.S. railroad electrification projects used 25 Hz for >just this reason and were still using 25 Hz up to a few years ago, though >the economies of custom power generation/converison had vanished with the >advent of major power nets. > >Don't ask me why they didn't use 30 Hz... Only true to a point. True eddy current losses are less but because more iron is necessary as frequency drops, the eddy current benefit is canceled. When one cosiders that manufacturing trickery can reduce eddy current loss to a very low value, the cost of increased iron is significant. Another factor is that a larger core will require more copper for a given amper-turns. This will increase IR losses. Nothing I can find in my library would indicate either frequency has a marked advantage. Nor can I find any reference to the use of 50 vs 60 hz. I suspect that whatever answer is postulated will contain a component of folklore. It may end up being something as simple as 50 hz sounds "metric" while 60 hz sounds English. 25 hz electricity was used because slow speed motors can be build with fewer poles than 60 hz. This was important in railroad motors because direct drive is considered important. A much larger use is in steel mills where VERY LARGE motors are constructed to run on 25 hz and to drive rolling mill rollers directly. There is a certain advantage to eliminating gears on a 25,000 hp motor :-) John -- John De Armond, WD4OQC | The Fano Factor - Radiation Systems, Inc. Atlanta, GA | Where Theory meets Reality. emory!rsiatl!jgd **I am the NRA** |
mmm@cup.portal.com (Mark Robert Thorson) (12/14/89)
Lots of military surplus equipment is 400 Hz, 115 VAC, because aircraft benefit from smaller transformers. Army uses 28 VDC.
ifarqhar@mqccsunc.mqcc.mq.OZ (Ian Farquhar) (12/15/89)
In a sensible world we would use 64Hz, for obvious reasons. D
pt@ncrsecp.Copenhagen.NCR.dk (Per Troelsen) (12/22/89)
In article <2332@ektools.UUCP> kinsman@ektools.UUCP (Andrew A. Kinsman) writes: > > I was wondering if anybody on the net had any historical > information on why Europe is 50Hz? Did the standards > >Andrew Kinsman rutgers!rochester!kodak!ektools!kinsman When I studied Electrical Engineering I was told that the 50 Hz was chosen to make life easier for us engineers, because the term 2 * pi * f is so much easier to calculate for f=50 than for f=60 (everybody knows the value of 100 * pi, right ? ;-) Per Troelsen NCR Systems Engineering Per.Troelsen@Copenhagen.NCR.dk Copenhagen, Denmark ...!mcvax!dkuug!ncrsecp!per.troelsen Telephone: +45 38 330022 Telefax: +45 31 102362 -- Per Troelsen NCR Systems Engineering Per.Troelsen@Copenhagen.NCR.dk Copenhagen, Denmark ...!mcvax!dkuug!ncrsecp!per.troelsen Telephone: +45 38 330022 Telefax: +45 31 102362
root@bio73.unsw.oz (Karl Redell ) (12/22/89)
60Hz is used for timing considerations. 1 cycle = 1 second. Among other things, this simplifies the construction of clock motors. karl@bio73.unsw.oz
nurmi@etana.tut.fi (Nurmi Jari) (12/22/89)
From article <1242@bio73.unsw.oz>, by root@bio73.unsw.oz (Karl Redell ):
> 60Hz is used for timing considerations. 1 cycle = 1 second. Among other
I'd say that 60 cycles = 1 second.
Jari Nurmi # Tampere University of Technology
# /Signal Processing Laboratory
nurmi@tut.fi # PO Box 527, SF-33101 Tampere, Finland
(nurmi@tut.UUCP mcvax!tut!nurmi)# tel: +358 31 162 501 fax: 162 913mmcg@bruce.OZ (Mike Mc Gaughey) (12/22/89)
root@bio73.unsw.oz (Karl Redell ) [22 Dec 89 05:41:55 GMT]: > 60Hz is used for timing considerations. 1 cycle = 1 second. Among other > things, this simplifies the construction of clock motors. eh? -- Mike McGaughey ACSNET: mmcg@bruce.cs.monash.oz "It's today!" said Piglet. "My favorite day," said Pooh.
rjd@dell.dell.com (Randall J. Davis) (12/23/89)
In article <1242@bio73.unsw.oz> root@bio73.unsw.oz (Karl Redell ) writes: |60Hz is used for timing considerations. 1 cycle = 1 second. Among other |things, this simplifies the construction of clock motors. | |karl@bio73.unsw.oz Huh??? When did they change the definition of hertz? Disregarding that, what *difference* does it make for clock motors? Last I checked, there aren't any direct drive analog clocks out there (this said because most centrally controlled clocks are run off of one pulse/second through a solenoid setup, and hence aren't really analog though they use an "analog" face), so *all* clock motors are going to be geared down to run the hand movements, so what difference does it make if the gear train does a conversion of, eg. 3600:1 instead of 3000:1???? This isn't already time for the April Fool's postings, is it? Randy Davis UUCP: dell.dell.com!rjd
jgk@osc.COM (Joe Keane) (12/23/89)
From an ancient tome: %The standard of frequency in North America is 60 cycles per second. In most %foreign countries it is 50 cycles. As a general-purpose distribution %frequency 60 cycles has an economic advantage over 50 cycles in that it %permits a maximum speed of 3600 rpm as against 3000 rpm. Where a large %number of distribution transformers are used a considerable economic gain is %obtained in that the saving in materials of 60-cycle transformers over %50-cycle transformers may amount to 10 to 15 percent. This is because in a %transformer the induced voltage is proportional to the total flux-linkage %and the frequency. The higher the frequency, therefore, the smaller the %cross-sectional area of the core, and the smaller the core the shorter the %length of the coils. There is a saving, therefore, in both iron and copper. It is interesting to me that our electricity standards come directly from the fin-de-siecle work of Tesla and Westinghouse. With the exception of some very-high-end DC transmission, all power transmission and distribution is 60 Hertz, three-phase (with single-phase subsets). Certainly this was a good choice at the time, when transformers were high-tech and no one had heard of semiconductors. I wonder what the power system would look like if it were designed from scratch today. Maybe it would use 400 Hertz. This results in large weight savings in transformers. It's also quite a bit safer; you're more worried about getting burned than having fatal muscle contractions. Then again, reactance and phase shift become much more of a problem. There might be more use of DC. Almost anything electronic really works on low-voltage DC. But i don't think people are going to run +5 VDC through their houses though. Imagine going to the store to buy a new 1000 amp fuse! Then again, i have seen a lot of new 12 VDC lighting systems. Getting less radical, a while ago there was a kick to run 240/416V services to new houses. The idea was that big stuff would use the three-phase or 240V line-to-ground, and a small utility-owned autotransformer would supply a 120V phase as normal. The utilities would win big becuase they'd have less copper and lower losses in their secondaries. They also get better phase balancing from more three-phase loads and being able to switch each house's phase independently. I don't know what happened to this though. Anyone else have thoughts on these things?