Edison dynamo

[Steamchick]

Thanks Mark. Sounds good. I was simply going to slap the output through a bridge rectifier and see what volts and current are available. This is a 6v 1 AC unit at Wheel speed for 10 mph. From what I have read... It is a permanent magnet rotor around the outside of the stator, so the "hard-task" will be making a "simulated wheel axle" and drive from the steam engine. But the fun is working out the solutions to the hard-tasks. The circuit diagram will be a help as I don't know about voltage control after the power is generated... when you can't control the excitation.
Thanks,

 

[Steamchick]

I found the "round tuit" - I have started making the "Whizzing magnet" generator. A very simple design so nothing to talk about - just needs a bit of time applied at the lathe...
But I have a question about the Edison DC generator. Are the field coils in series or parallel with the armature? Back in the 1970s I was converting motorcycle generators on engines that had 6V DC generators (Lucas, Wipac, Eastern European of East German and Czech bikes, etc.), as well as those with 6V alternators, to give a 12V controlled DC output, using a bulb to give me the resistance I needed in series with the field coils to avoid cooking the field coils, and I re-wired the electro-mechanical regulators for a 12v armature output. - I am pretty sure I remember the fields being in parallel with the armatures - via the regulator. I also bought a "transistorised regulator and 12V DC conversion" for 1 bike, before I started converting the PAL and other regulators.
But I now have some electric drill (mains) brush motors, which have the field coils in series with the armature - presumably as the motors run from AC and "rectify" by the field switching in phase with the armature? I have wondered, if I can re-wire one of these to act as a generator (directly driven from a steam turbine perhaps?) by setting the field coils in parallel with the armature and fitting a regulator - as per the pre-1970 vehicles? I am aware that there are a variety of configurations for winding armatures, and note that the brushes often cover more than 1 pair of commutator contacts at any time (copper strips much narrower than the brush width)... I wonder if I would have to rotate the brush alignment from the motor application? - Or would it require the generator to run in the opposite direction to the direction i was designed to run at as a motor? I'm sure someone has done this and has the answers to save me re-developing the solution. - Thanks.

 

[skyline1]

Older electric drill motors and many domestic appliance motors are what are called "universal" or AC/DC type. They are series wound D.C. machines that can be run on A.C. as the field polarity changes in sync with the armature polarity as you have pointed out. This actually applies to many D.C. machines.

They are fairly compact and powerful and above all cheap to produce. (we are back to that old chestnut again, economics) but they have several disadvantages.

They usually need to run at high speed which makes them noisy (very noisy sometimes) and entails a reduction gearbox to give higher torque and lower speed.

They have a high brush wear rate and a tendency to "eat" their commutators if the brushes get worn. You see many old drills still going but "sparking at the comm" in a most alarming manner.

They can produce large amounts of Radio Frequency Interference (RFI) and need to be well suppressed (Ask any Sound Engineer or Radio Amateur)

But even with their shortcomings they are pretty reliable and rugged and we have been using them for years in all manner of applications.
Speed control can be arranged by using simple SCR phase control (basically a ruggedised light dimmer)

Recently however there has been a trend towards using "brushless D.C. or Digital motors" in these applications, This is a slight bending of the truth as there is no such thing as a true brushless D.C. machine. What they actually are, is a miniaturized 3 phase A.C. machine coupled to an equally miniaturized Variable Frequency Solid State Drive, No Mr Dyson you didn't invent it Tesla did many years ago.

Using one of these "universals" as a generator might be possible but there are several snags

I suggest you go with them "as is " putting the existing field winding in parallel instead of series would not work as it's resistance is far too low it would simply use most of your power turn it into heat and probably burn out the armature winding. designing a new field with more turns but thinner gauge wire is beyond my ability I'm afraid but other members with more knowledge (and superior maths skills) might like to have a go at it.

They are pretty powerful in the order of several hundred watts, so you would need a big turbine to drive them and the efficiency (or lack of) of a single stage De Laval or Stumpf Like I use would mean a big fuel and water guzzling boiler. A small scale multistage like a Parsons type would give you the efficiency but the complexity of design and construction probably make it impossible (and expensive)

But "Doing the Impossible" is a theme here and judging from the Merlins, V8s and Radials some have built, someone is likely to likely to have a crack at it.
The model jet chaps would have the required expertise and equipment for example.

Best Regards Mark

 

[Steamchick]

Thanks again Mark for another bit of clear thinking, and advice.
That helps me get on the lines of what to study, and consider for re-engineering one of these motors as a generator. I now realise I need to check-out the motor, to understand the field resistance and armature resistance. Then consider the limitations of a generator for the speed I expect to be able to drive it at. As well as the max permissable current in both armature and field coils. I reckon I can check it simply with my AVG meter, but also check voltage drop across the field coils and armature when I drop 12v DC from a car battery across the motor "as it is". I suspect I'll get into calculations comparing the impedance at 50Hz (As the motor is rated for 240V, 50Hz.) with the resistance at DC.... but, here is the nitty-gritty... do I need to consider the impedance of the armature at rated speed for the effective "AC" I each windings it is energised then de-energised as it passes through the magnetic field when I use it as a generator?
One of the contributors to the Edison Generator thread has used an armature from a electric motor, and wound the field coils for the Edison dynamo. So what speed is it running at to use in this application, what resistance of armature, and how many turns and what wire make the field coils, and what are the relative currents in field coils and armature when running? - Please forgive all the questions, and I think the design was yours but I haven't got that bit of thread to know the author.
The thing is, I suspect the Electric drill motor that I am considering converting, may be limited by current simply because running at AC the field coil and armature impedance (inductance) is the current limiting factor, not the resistive element alone. So supposing it was run on DC, at the same voltage as RS mains, I may expect it to burn-out from overheating as the energy of oscillating the magnetic field isn't there with DC to limit the current...? Or have I got my ideas "out-of-phase"? I'll start looking at the motor and try doing the sums, then let you know my conclusions - then I may consult Maxwell
(James, the one who wrote the text books!), although I last read his books 45 years ago... But Tesla understood Maxwell.
Regards,

 

[Steamchick]

Flippin' spell checker again! AVG should be A V O, it manages "nitty-gritty" but not "Tesla"! - and "Edinburgh son" or "Editor" for Edison? Makes me wonder....

 

[skyline1]

Ah James Clerk Maxwell (1831 - 1879) James Clerk Maxwell - Wikipedia another misunderstood and under appreciated genius.

(oops I can feel another rant coming on so back to dynamos)

Yes rotating machine design whilst the basic principles are simple can get very complex, very quickly. So before you go completely potty and start quoting Maxwell's Equations to your therapist I think I may have a cheap and almost ready made solution,

What about the armature from a cordless drill they are D.C. and rated for about the right voltage and current you need.
They are very rugged in fact almost indestructible. (they need to be in a machine that has to withstand regular overloads and even complete stalls).
The best bit is they are likely to be cheap or even free as people often chuck out usable cordless drills because the battery or charger has died or is too expensive to replace. The field assembly and brushgear from the existing miniature Edison that quite a few have built should match quite nicely with one of these.

Meanwhile it will be interesting to see how your Duplex "whizzy magnet" machine develops keep us posted on how it's going.

Best Regards Mark

 

[awake]

Luckygen1001 on YouTube has quite a few videos on converting motors into generators - might be helpful?

 

[Richard Hed]

Thanks again Mark for another bit of clear thinking, and advice.
That helps me get on the lines of what to study, and consider for re-engineering one of these motors as a generator. I now realise I need to check-out the motor, to understand the field resistance and armature resistance. Then consider the limitations of a generator for the speed I expect to be able to drive it at. As well as the max permissable current in both armature and field coils. I reckon I can check it simply with my AVG meter, but also check voltage drop across the field coils and armature when I drop 12v DC from a car battery across the motor "as it is". I suspect I'll get into calculations comparing the impedance at 50Hz (As the motor is rated for 240V, 50Hz.) with the resistance at DC.... but, here is the nitty-gritty... do I need to consider the impedance of the armature at rated speed for the effective "AC" I each windings it is energised then de-energised as it passes through the magnetic field when I use it as a generator?
One of the contributors to the Edison Generator thread has used an armature from a electric motor, and wound the field coils for the Edison dynamo. So what speed is it running at to use in this application, what resistance of armature, and how many turns and what wire make the field coils, and what are the relative currents in field coils and armature when running? - Please forgive all the questions, and I think the design was yours but I haven't got that bit of thread to know the author.
The thing is, I suspect the Electric drill motor that I am considering converting, may be limited by current simply because running at AC the field coil and armature impedance (inductance) is the current limiting factor, not the resistive element alone. So supposing it was run on DC, at the same voltage as RS mains, I may expect it to burn-out from overheating as the energy of oscillating the magnetic field isn't there with DC to limit the current...? Or have I got my ideas "out-of-phase"? I'll start looking at the motor and try doing the sums, then let you know my conclusions - then I may consult Maxwell
(James, the one who wrote the text books!), although I last read his books 45 years ago... But Tesla understood Maxwell.
Regards,

Just so you know, Oliver Heavyside is the guy who really is responsible for "Maxwell's" Equations (that is the ones about what light is)--Maxwell had 20 equations which Heavyside reduced to the four now known as "Maxwell's Equations". Really, they should be known as the Heavyside-Maxwell equations. Anyway, Heavyside was an underknown, under-acknowledged, unappreciated genius of the electric age. His stuff is in magazines all over the place, particularly in one magazine (don't remember which, but am sure it has the word "electric" or some derivation of that in it) which he wrote for. Look up Heaviside (sp?), he has very much of what you might be looking for.

 

[skyline1]

Yes quite so he reduced Maxwell's correct but rather long winded ideas to something more manageable among his other many accomplishments including research into Characteristic Impedance leading to the development (and patenting) of the coaxial cable.

I think Europeans and the British in particular have a tendancy towards science as an end in itself whereas Americans are more open to the commercial and practical applications of ideas, which may explain why many European scientists tend to be less well known.

Best Regards Mark

 

[Richard Hed]

Yes quite so he reduced Maxwell's correct but rather long winded ideas to something more manageable among his other many accomplishments including research into Characteristic Impedance leading to the development (and patenting) of the coaxial cable.

I think Europeans and the British in particular have a tendancy towards science as an end in itself whereas Americans are more open to the commercial and practical applications of ideas, which may explain why many European scientists tend to be less well known.

Best Regards Mark

It just irritates the heckout of me when I read "Maxwell's" equations, when realistically, they are WHOLLY Heavisides. He did derive them from Maxwell, but still they are NOT Maxwell's equations! Incidentally, did you know Heaviside is the REAL inventor of radio? He demonstrated in 1888 (I believe) that he could transmit a signal from one side of a room to the other. Then he quit. That was enough and very few peeps knew about this. Yes, as you say, he failed to exploit this for commercial purposes. Heaviside is a real hero and he should be better known. I thimk I downloaded a bundle of his magazine articles. But trying to find them might be a difficulty. They are freely available if you know where to look.

 

[Steamchick]

Hi Richard, I apologise for quoting Maxwell instead of Heavyside... I have not heard o Heavyside, so again this blog has taught me something more than school. The reason I consult Maxwell, is the text book Ho wrote, I have my Grandfather's copy from his schooling, dated 1890 somthing. Maxwell made fame amongst his peers, FRS, University top-dog, etc. And was (is?) Used as the text book since he wrote it until at least 1980s in the UK. But there are many clashes of ownership of ideas, and mostly the richer people with better (more business) sponsors won the accolades. Just look at what Edison did for Tesla, Bell, Swan, et al. And James Watt, versus Trevethick, Newcomen, & co. Nuff said. Back to spinning magnets!
K

 

[Richard Hed]

Hi Richard, I apologise for quoting Maxwell instead of Heavyside... I have not heard o Heavyside, so again this blog has taught me something more than school. The reason I consult Maxwell, is the text book Ho wrote, I have my Grandfather's copy from his schooling, dated 1890 somthing. Maxwell made fame amongst his peers, FRS, University top-dog, etc. And was (is?) Used as the text book since he wrote it until at least 1980s in the UK. But there are many clashes of ownership of ideas, and mostly the richer people with better (more business) sponsors won the accolades. Just look at what Edison did for Tesla, Bell, Swan, et al. And James Watt, versus Trevethick, Newcomen, & co. Nuff said. Back to spinning magnets!
K

I wasn't criticising you, it's just that Maxwell certainly deserves the credit for the work he did on light, but even so, in all the books, those four equations are given as "Maxwell's Equations" when indeed, they are NOT! This is in ALL the books I have ever seen. I thot they were Maxwells equations till I discovered that they were Heavisides stuff. I was reading some of Heaviside's writing when he told how he came up with them. No one in their right mind would bother with maxwells original 20 equations when they could use Heaviside's simple 4 equations (in various forms too).

What I thimk is more important is to learn about Heaviside and his very important contributions to electrical thot and function. He was very much like Tesla except without being very well known at this time. He was better known 100 years ago. He also made some important discoveries in Calculus in which the mathematicians complained that he had not "proved" what he was doing (only used it in electrical calculations). Later, some mathematician "proved" it.

 

[Steamchick]

I think of the simple Phase "Standing on the shoulders of Giants"... Well, we all are... Modern Technology comes from a collective of the incredible thoughts of mankind... "Never in the History of Man can we say we owe so much to so few.." - to quote another giant.
I consider the length of the "stone age". "Bronze age", "Iron Age". .... modern "iron and steam age", "Electrical (power) age". electrical "Communication age", "Aeronautic age", "Oil (materials) age", "Nuclear age".... etc.... We are even communicating globally via the electrical "Communication age" - which is a veritable "Tower of Babel"! - Started by Tommy Flowers....? - Or was it started by the German teleprinter engineer who invented the Lorenz machine? So where next? And how fast will we learn to live within new ages? - I'll get back to the fundamental building block of whizzing magnets! - And I can do most of it without even reading Heaviside's and Maxwell's equations... But they will solve some problems before I "cut-metal". - So maybe that is the "Beautiful lesson" for today? - "Brain work" can save a lot of wasted "workshop time"! - Oh... I may have started a new debate....

 

[Steamchick]

Hi Mark,
I have learned from Utube videos that the series brush motors will generate DC when spun in the correct direction (still getting my head around that one?) - and anything up to normal running speed (thousands of RPM!). They need a load (resistance /conductance) to close the circuit and the EMF developed across the Armature then drops volts - Through brush resistance, field coil resistance (not impedance as DC is being used), then load resistance (conductance). As the resistance of the total circuit drops (limited by load being short-circuited and all the load seen by the armature is the internal resistance of the whole motor/generator) then the current increases - so power output increases as the load gets bigger - up to the limit. But re-wiring with Field coils driven by a regulator will simply make a "traditional" dynamo - which I think is the direction I may try first. I have learned that the application of AC to these motors is limited significantly by the AC frequency across an inductance: I.E. the impedance. Therefore as a DC machine (especially with Parallel field coils) they have completely different properties to there designed use as "AC. High speed" motors.
Thanks everyone for the tips!
Ken

 

[Richard Hed]

I think of the simple Phase "Standing on the shoulders of Giants"... Well, we all are... Modern Technology comes from a collective of the incredible thoughts of mankind... "Never in the History of Man can we say we owe so much to so few.." - to quote another giant.
I consider the length of the "stone age". "Bronze age", "Iron Age". .... modern "iron and steam age", "Electrical (power) age". electrical "Communication age", "Aeronautic age", "Oil (materials) age", "Nuclear age".... etc.... We are even communicating globally via the electrical "Communication age" - which is a veritable "Tower of Babel"! - Started by Tommy Flowers....? - Or was it started by the German teleprinter engineer who invented the Lorenz machine? So where next? And how fast will we learn to live within new ages? - I'll get back to the fundamental building block of whizzing magnets! - And I can do most of it without even reading Heaviside's and Maxwell's equations... But they will solve some problems before I "cut-metal". - So maybe that is the "Beautiful lesson" for today? - "Brain work" can save a lot of wasted "workshop time"! - Oh... I may have started a new debate....

That's perfectly all right. It's better to thimk than be a couch potato. It's better to have some ambition than be a dead beat, 'cause dead beats just expect a handout. My son talks about what you have mentioned above and he says that the discoveries of fire, copper, bronze and all those other slowly developed inventions/discoveries are worth billions in todays dollars. Those discoveries were all necessary for us to have the civilization we have today. The single most un-appreciated chunk of technology we have today is Sewers! They are hidden below the street, they save us from cholera, typhus, stink and who knows what else? And yes, reading a few articles can save us lots of time. That's also why we have this and other forums. It's like some of us know one sector and others know another.

BTW, I managed to cut some internal threads today on my crappy enco lathe. I had to build a hand wheel to do it and turn the thing by hand because the enco could not go slow enough for me to stop it at the end of the threads. It was a great pleasure to do this. Am starting another, identical set of threads tomorrow. These are for the internal threads to an ER-25 and 11 collets using a 1-1/2" X8tpi spindle nose. Also, I had to grind a 60deg thread cutter out of carbide which wasn't so bad and then to silver solder it to a holder. That is the first time I ever did silver solder and didn't have much hope for it to hold together (experience with mere lead solder), but it held very well and workt just fine. Very happy about that.

 

[awake]

One of the things I have found most fascinating, when I have visited archaeological sites in Greece and Turkey, is the fact that cities they had systems for dealing with water and waste - 2000 years ago and more. When you think about it, you really can't have a city without some way to handle at least the water issue. You could have privies out back for the waste, as was true in many a western city up until relatively recently (recently in the time scale we are talking about) - but in these 2000 year old cities, they had indoor toilets, with water washing through them to clean them out. I also saw a village on Thera (Santorini) that was covered by volcanic ash and preserved more than 3000 years ago - and in one of the houses, on the second floor, there was an indoor toilet - though I couldn't see how the waste was handled. All this time, I had thought the invention of indoor plumbing was a modern miracle ... apparently not!

 

[awake]

Also, I had to grind a 60deg thread cutter out of carbide which wasn't so bad and then to silver solder it to a holder. That is the first time I ever did silver solder and didn't have much hope for it to hold together (experience with mere lead solder), but it held very well and workt just fine. Very happy about that.

Richard, out of curiosity, why did you grind the thread cutter out of carbide instead of HSS? Were you threading particularly hard material?

 

[Richard Hed]

Richard, out of curiosity, why did you grind the thread cutter out of carbide instead of HSS? Were you threading particularly hard material?

Probably because I don't know any better. I also have tons of carbides that have no holders. I wanted to test out the silver soldering--never done it before--works great. The material I am cutting is hydraulic piston rods--don't know the exact stuff. Do you suggest I should try silver soldering HSS? I suppose I could use a HSS in a boring bar of some sort--there is a hole all the way thru the part.

 

[awake]

Hmm, hydraulic piston rods are likely to be hard on the outside; not sure if they are hardened through. And I apologize - I missed the fact that you were doing internal threads. I was thinking of how much easier it would be to grind an external threading tool from an ordinary HSS blank. You can grind an internal threading tool from an HSS blank, all in one piece - I have done it, successfully, but it is a persnickety process. Silver soldering a bit ground to 60° onto a bar is going to be way easier and less error prone. And if you are going to sliver solder the bit in place, then the only reasons to go with HSS rather than carbide would be if you don't have carbide handy or don't have the means to grind it easily - sounds like neither of those apply in your situation. Carry on!

 

[Richard Hed]

Hmm, hydraulic piston rods are likely to be hard on the outside; not sure if they are hardened through. And I apologize - I missed the fact that you were doing internal threads. I was thinking of how much easier it would be to grind an external threading tool from an ordinary HSS blank. You can grind an internal threading tool from an HSS blank, all in one piece - I have done it, successfully, but it is a persnickety process. Silver soldering a bit ground to 60° onto a bar is going to be way easier and less error prone. And if you are going to sliver solder the bit in place, then the only reasons to go with HSS rather than carbide would be if you don't have carbide handy or don't have the means to grind it easily - sounds like neither of those apply in your situation. Carry on!

I have limited tools, green stone for grinding the carbide, will attempt to buy a diamond grinder this year, but always the factor of limited funds. Anyway, I am in the process of making tools to make the tools for making the parts. I have known for many years that that is what a machinist is, a person who makes tools for making parts, often a tool to be used exactly once! Hopefully to be used often. So am making ER for quickly being able to change parts out and be accurate in doing so. (As opposed to fiddling with the 4-jaw). It's very much fun and satisfying but slow too.