But I learn so much when the topic takes a detour BECAUSE youall are far more knowledgable than just cars…that’s a good thing.
The caveat however…I can’t remember which car topic had the segue when I want to add or rread more 
“$100 a month for a teacher in the early '30s was a very good salary”
I think that a lot has to do with the cost of living in a particular area, and for the particular individual. My mother began teaching at the height of The Great Depression, in NYC, and she was paid $5.00 per day. That works out–more or less–to $100 per month, which was not a “very good salary” in NYC–especially in view of the reality that no pay checks arrived during the months of July and August.
On that $1,000 per year, she had to pay the rent for her parents’ apartment, the medical costs for her extremely ill father, as well as food and clothing for the entire extended family of 6 people, as well as her trolley/subway fare to work… If not for a free allotment of coal in the winter (due to their perilous financial situation), they would probably have frozen to death in their apartment.
Thank you Keith,it is as high as an effiecency gain of almost 10%(loss in the rising and collapsing fields)AC is better for small voltages,you can transform it so easily,I suppose though,that 110 volts dc would probaly deliver the same wattage through an equal size conductor as 110 AC,this discussion has started something clicking in the background of my Mark 1000,pertaining to the nature of electricity(Tesla and Steinmetz understood electricity perhaps better then other folks)I do believe a high voltage DC,may cause a few a few more problems with arcing and whatever,the threshold of arcing is sort of agreed at 18volts,
There was serious discussion of raising the standard operating voltage of Automobiles to 48 volts.thank goodness cooler heads prevailed,there would have been a whole host of problems had the manus,done this.
Electricity behaves like a fluid(think juice) and will mostly always seek the easiest path to return.We see a lot more electrical related issues as more cars and vehicles switch to electric drive.
It was 42 volts that was being considered and you will see it or something similar eventually. You already see much higher voltages than this in hybrid cars. The threshold of arcing is any voltage that exceeds the dielectric constant of the insulation whether it is one volt or one million volts.
Generally 60 volts DC is the threshold for skin penetration for electricity, but that is not a fixed value, it changes with different people and different environments. But in the pursuit of higher gas mileage, I think we will have to go to higher voltages. Things like electric compressors for AC, electric water pumps and solenoid operated valves will not operate very well at 12VDC.
They’ve been able to greatly increase the efficiency of the electrical systems, so 12v is enough for non-hybrids.
Keith, I read with interest, your post regarding phase shift and I respect your knowledge on that topic. A big problem with using 42 volts d.c. in autos is the arc interruption capability of inexpensive, simple, and small switches. 12 volts is not difficult to interrupt at moderate current levels but as voltage rises to 42 volts, ordinary switches won’t work unless current values are very small. Inductive loads make the problem of d.c. arc interruption quickly more difficult than with resistive loads. Large commercial d.c. contactors use electromagnets that operate from the current flow being interrupted or else use permanent magnets, either of which pushes the electric arc having it’s own magnetic field from current flow into lengthening into a safe area within the contactor until the arc becomes too long to be sustained. 42 volt auto switches would also need magnets or exceedingly large open contact gaps to do this. In comparison, a.c. arc interruption is easy because the voltage goes to zero 120 times per second. The difficulty of switching d.c. power, especially in the early days, is another reason why a.c. won the current war.
Tester asked why an auto alternator did not need a current regulator like an old fashioned generator did. The reason is magnetic saturation of the alternator’s stator. A piece of iron with current flowing through insulated copper wire wound around it will become more strongly magnetic to where magnetic saturation of the iron occurs and the iron will not become a stronger magnet no matter the current flow through the copper wire or the proximity to a nearby, much stronger magnet. That is what limits alternator current output.
When this thread attracted 165 responses, I don’t think the board is fading away. I wonder if our discussions about Norwegian composers, gas refrigeration, and alternating vs direct current might have scared him off.
Yeah now that we’re counting, 3700 views. Not bad. I’ll have to admit my eyes glazing over talking about AC versus DC but it seems to perk up the engineers on here. A fun history book called " The Men Who Made America" has a section dealing with the beginnings of electricity here (in the US) and was interesting reading for me. I’m not into phase switching and arc interruption though unless I’m welding-then arc interruption is common.
There is currently a lot of battery powered lawn and garden equipment that use 40 to 58 volts, so I guess switching isn’t that big of a problem. Most of the equipment uses an electric motor so the load is inductive.
It may be a few years yet, but I do think that 12V is on the way out. But then, a few years ago, I thought it would be gone by now. I had also expected/hoped to see computer controlled, solenoid operated valves by now.
I didn’t have electrical or starting problems with the 6 volt systems in my 1947 Pontiac, my 1948_Dodge, or my 1950 Chevrolet 1 ton pickup truck. The Dodge and Pontiac had vacuum tube radios that consumed a lot of power. The Dodge even had electric wipers. I will admit that the 12volt systems are better and the alternators are superior to the generators, but the 6 volt systems worked well for me even in zero degree weather.
I do have a 24 volt rechargeable battery mower. I haven’t had any switch problems. I bought it second hand as an experiment to see how well if stacked up against a gasoline mower. It does quite well,although the batteries make it heavier to push.
Speaking of higher voltages, in the newer buildings on the campus where I taught, the lighting circuits are 277 volts. With three phase power, this is the voltage from one phase to ground. I have noticed when I have purchased ballast coils for fluorescent lights and lighted EXIT signs for the church I attend that these devices have a 120 volt connection and a 277 volt connection. The church only has single phase power so the lighting circuits are 120 volt.
Speaking of higher voltages, in the newer buildings on the campus where I taught, the lighting circuits are 277 volts. With three phase power, this is the voltage from one phase to ground.
This is one phase of a standard 480V, 3 phase system. Many office buildings are wired with 208V, 3 phase so that one phase is 120V (square root of 3 multiplier) and motors can run off the 3 phase.
Triedaq, there are a number of three phase secondary voltages available. That is the beauty of using AC and transformers for distribution power. You can have three phase secondary voltages of 208Y120, 120D, 240D with or without a 120 single phase tap, 480D or 480Y277. Y stands for a wye wound (4 wire connection) circuit and D is a Delta wound circuit (three wire connection). This is important for how the three phase motors are wound.
There are others but these are the most common, the 480Y277 is the most common for three phase as there is usually a very large motor involved somewhere. Almost all industrial motors are 480 volts, either wye or delta wound.
BTW, I had a 60 Borgward that was 6 volt + ground.
Edit: corrected 120Y to 208Y120.
About this three phase voltage, while I’m totally a DIYer re AC wiring I found myself facing wiring up a three phase motor on an air compressor many years ago and using my best judgement wired up the motor and it ran for many years without a problem but I understood that there was a 220v and 2 110v leads and as best I can recall it was considered a 440v motor. I will admit that I was somewhat concerned when I threw the switch the first time. Where can 277v be found between/among the 220v and 110v sources? And I do understand that the voltage is the positive to negative potential.
440V has been replaced by 480V just as 110/220V has been replaced by 120/240V. I sincerely doubt your 110/220V leads were directly associated with the 440V 3 phase. It would require another transformer, which was probably the case.
In a wye (Y) circuit, you have line to line (aka phase to phase) voltages and line to ground voltages (aka phase to ground). In most industrial motors, 480 is the rated voltage and it is line to line, whether Y or delta wound.
480 and 440 are essentially the same. 480 is the voltage at the transformer’s bushings. When the motor is running, the wires from the transformer will drop some of the voltage, typically down to between 440 to 460 volts.
Same in a house. The voltage at the transformer bushings is 240/120 but in the house under normal loads, the voltage at the outlets are between 110 and 115 and 220 to 230 at the big appliances.
I know our buildings all had 277v lighting. I don’t understand it but that’s ok.
When I was a kid in the 50’s one of our neighbors had a real electric lawn mower. No batteries. He had about a 200 foot cord that plugged into the house so he could reach everywhere. This was before GFI circuits and no one had any outlets outside-usually not even in garages.
There was no transformer in the shop wiring @insightful. There were 3 hot wires, 2 110v and one 220v and of course the neutral and ground. A dedicated 3 pole circuit breaker was there when I rented the building which had been built as a shop for a local electical contractor long ago. As a rule line voltage here is about 117v on each leg but it is rated 110v.
The alternating three phase power allows for motors designed for three phase power to start heavy loads. However, there are no phases for direct current. I assume that direct current (d.c.) motors can be designed to start heavy loads. If building in New,York City had only direct current available, these direct current motors had to be able to run elevators. I wonder if these d.c. motors could also run on alternating current. I assume these motors were brush type motors. I know that there are a.c. motors,that start as a series wound d.c. motor and then a centrifugal switch kicks the brushes out and the motor runs as an induction motor, so I am guessing that these big d.c. motors could be changed over to a.c.
Bing, 277VAC is common or industrial lighting, especially florescent lights.
Rod, What you describe sounds like a rare circuit called a open delta, but the motor would be operating far below its potential. A large motor could be reused for another purpose that doesn’t require its full output. A 240D open delta would be half voltage for a 480 V motor, and there would be another 46% reduction in output by using a open delta instead of a full delta.
This was common in the early 50’s for residential homes with early air conditioning systems. The AC units were either 120 or 240 delta wound motors and the utility would use two transformers instead of three in the corner delta configuration. I don’t think any one does that anymore. It isn’t very efficient.
Edit: You should not have had either a neutral wire or a ground wire. You could have one, but not both with an open delta or you should have had two 240 volt wires. I kinda suspect that you didn’t or should not have had a ground.