We here in Australia have one of the highest voltage power supplies in the world at 240 V which makes for a very efficient reticulation of power but it does lend itslf to electrocutions from time to time. Smallerconductors and more eevn voltages available as well.
60 hz seemd better to me with smaller components such as inductive devices.
This should interest most people as it applies to both sides of the Atlantic from a different direction and evn to us downhere in the South western Pacific.
I would daresay that most utility customer’s don’t have much of a choice in the matter. 120v is standard issue, 240v is available to US customers. My garage is set up for 120 and 240, with the 240v on special installation. I use the 240v to run my welding equipment.
I don’t see where 240v could benefit a garden RR, we have a tendency to step down voltage to 25v or less for most of what we run. 120v step down would create less heat and therefore be more desirable for an electric train.
Actually since most of us use household current for whatever propulsion - stepped down, charged or trickled out - I’m not all that concerned about “relative efficiency”. I’m sure more power trickles away in whichever house we live, that worrying about the waste on the GRR is a waste of time. [;)][:D][;)]
I recall an article called “Looking Back” in Mentally Ret…ooops…Model Railroader years ago by former editor John Gage, I think.
Guy had built a trolley line in his basement, on the concrete floor, using vacuum cleaner motors and live overhead…with 110vac as power.
Described the thrill re-railing a derailed engine with power on…
This comparison is not just to do with Garden railways but to consumers in general which we all are!
However I do know that it will affect garden railways where a long extension cord is involved. Voltage drops are more prevalent in 110 V systems whereas electrocutions are more likely with 240 V systems.
Do you know any of the historical background as to how Australia wound up with 240 Volts as the mains standard?
In my 26 years of travels around the world in the U.S. Army I encountered voltages from 90 to 220, and Hertz from 50 to 400. 220 Volts at 50 Hz seems to be the most common throughout Europe, with 90 to 100 Volts at either 50 or 60 Hz throughout the Far East (Japan, Okinawa, Korea, and Vietnam).
In the U.S., nearly everyone says our current is 110 Volts at 60 Hz, but it’s actually 117 Volts peak-to-peak. 110 Volts is the RMS reading.
Anyone fiddling with electricity that’s provided to the residence or business better have their wits about them.
Running a long extension cord to power a permanently set up GRR is not the smartest solution in the first place, even less so if the extension cord gets plugged into a non-GFI protected outlet.
OTOH I have seen a professional electrician plug in an asymmetrical fuse box into a 550v bus bar - the wrong way around! Well, it was one loud bang and Mr. Sparky sailed across the aisle. Was good for a week of time off with very fuzzy vision.
This just as an example for “if the profs can screw up, the amateurs better watch out!”
Yep, all household voltages are measured peak to peak, rms is rarely used except when figuring out what rectifying it to DC is anticipated, or trying to measure DCC.
Peak reading meters are somewhat easier to build apparently, also if you look at the power on an oscilliscope, it reads peak directly.
Au Contraire. The nominal 117 volts, or 110 volts, is the rms value. Peak to peak would be about 330 volts. Peak to peak is sometimes talked about in hi-fi but not in household voltage. TOC knows what he’s talking about even if this isn’t battery powered type stuff.
As years go by, some things change but some stay the same. Peak times .707 (root 2 over 2) is RMS. Peak times .636 is average value of a half sine wave, not too useful. And peak to peak is peak times 2, interesting and useful in some circuitry.
You’re right again TOC, RMS times root 2 which is 1.414 is the peak value and of course the same value can be gotten by dividing the RMS by .707. I suppose if I looked in some book somewhere I’d find why I remember .636 but 'taint worth it. Strange what the brain remembers - like the phone numbers of the student nurses I dated back in 1945/46!
Well, as I was taking a shower, getting ready for bed, the signifcance of the .636 average value of a half cycle of a sine wave emerged from the depths.
A DC meter reads AVERAGE values. A ripple on a DC voltage does not affect the meter reading because the average of a full sinewave is zero.
To measure AC voltages, the ordinary multimeter places a diode or rectifier in series with one lead. The meter will now read the average of the wave form it sees but it doesn’t see the full sine wave.
Since it sees only the positive half cycles, it registers not .636 of the peak voltage but only half of that or .318. Of course the scale is calibrated to read RMS as that is what is important in power equations and consumption.
The diode/rectifier has a voltage drop across it and this drop is not linear across the range so the AC scales on most multimeters are not as linear as the DC scales.
I think this classifies as TMI - or maybe WTMI - Way Too Much Information.
It’s a completey different ball game, though, for peak reading meters.
I’m finding this interesting, artscholosser. Sure, it’s off topic, but it’s better than opening the topic for “Newspapers On Line” over and over again because the forum software thinks I haven’t read it yet.
Who knows, it may just come in handy some day on someone’s railroad. (220 out in the garden anyone? (Actually, now that I think of it, that’s not too bad of idea. (It is, but it isn’t.) Using standard lights and outdoor fixtures would be a good way to light your path.))
To make things more confusing, in at least the Netherlands and Germany 220 V really is 230 V nowadays, it was upped a bit about ten years go. We can also get the more industrial 380/400 V, known over here as power current. Put that on your tracks overnight and you might wake up to the smell of barbequed cats and hedgehogs…
Some electrical education for the masses, and some things you never knew and maybe NEVER wanted to know…
First, AC voltages are measured RMS, except possibly in a lab where they’re using an oscilloscope. It is a pretty clean sinusoidal waveform, unless harmonics are introduced into the system. The square root of 2 comes into the calculation when comparing peak vs. RMS voltage. A 120 volt signal will have a peak voltage of positive 170 volts and minus 170 volts. It wiggles back and forth at 60 times a second here in the U.S. Some say it must be a woman because it can’t decide what it wants to be…
Another confusion factor is that you CAN have a peak-reading RMS voltmeter! This does not measure the peak voltage of the waveform (170 volts) but the peak RMS voltage measured over the period of time that you have the meter attached. This comes in handy when you’re watching the line voltage bounce up and down. They also have minimum-reading meters as well when you want to know how bad the voltage sags when a motor kicks on. These same meters can be used to measure the peak and minimum DC voltages as well, so you could hoook them up to your rails and REALLY know what was happening to your system, handy, eh? These meters won’t however do a decent job reading the a
Hey everyone,
Well Ian you have a well deserved response from this one. Only recently did I learn from an electrician friend that rewiring my air compressor for 240 would solve my tripping the breaker problem. The unit draws 15.0 amps on 120V. Whereas on 240V the draw is only 7.5 amps. Another benefit is added motor life as a result. The compressor would run fine on the initial fill but would trip the breaker as soon as refilling the tank was required. This was frustrating indeed since the label had it rated at 15.0 amps. My shop is already running the required voltage so a new plug for the compressor goes in shortly. Incidentally a friend of mine owns a sheet metal shop that was once all powered with 440V. I believe that was what it was anyways. Our ancient trolley bus system provided the necessary power. His shop is chock full of ancient metal working equipment. He even has the stapler necessary to attach weatherstripping to the run channel on antique car windows. Those big electric motors now sit silent in his shop. A pack rat for sure. Later eh…Brian.
I always like detailed posts from someone who actually works in the field and knows what the tolerances, causes and consquences are.
But I don’t really worry about our 120V supply, experience tells me that even at the low end of the tolerance, trains will still run. Of course I’m one of the crazy guys who uses stranded AWG#18 even for N scale, instead of the salvaged telephone wire. Yes, that’s my very own fault. [;)][:)][8D]
