Saturday, September 24, 2011

2 parts in 100000

At first glance it sounded exciting. Neutrinos traveling faster than the speed of light.

Then I started to read the commentary. The speed of light is: 299,792,458 meters per second; the speed the neutrinos were measured at is 299,798,454 meters per second. A velocity difference of about 2 parts in 100,000. Since they did 10,000 tests this might show some minor correction to relativity. More likely they measured a distance incorrectly.

A much better comparison came from detecting the light and neutrinos from a super nova. Sure enough when this has happened the light and neutrinos arived at the same time.

Thursday, September 22, 2011

More vetoes

And Jerry Brown earns more points by vetoing a bill restricting medical marijuana while signing a bill removing the ban on infused alcohol drinks and making internet shipments of wine easier to make. There is still hope that the long descent of the Democratic party into the nanny state party will recede.

Tuesday, September 20, 2011

Real time electricity use in California

I recently found out that you can get graphs for daily electricity use, wind production, and solar production in the state of California.

This doesn't have much real value for me, but watching it the last two days it became pretty clear that wind power has some issues. It is hardly producing at all when electricity use is at its highest in the afternoon. Unless we get some storage system capable of holding electricity at night then releasing it in the day time that could seriously impede the use of wind power. Instead of competing with high cost natural gas, it is competing with low cost nuclear.

Monday, September 19, 2011

Zoning laws

I have become increasingly against zoning laws. In particular, I am against any regulation which puts a maximum on the density in urban areas. This really does make the most sense of any explanation I have heard for why housing prices are so high in cities like San Francisco or New York City. When people cannot build new, higher density, construction they are forced to fight for existing properties. This bids prices way up over the price of construction.

Anyways, here is another article I have come across on this topic.

Robotic fast food

I just ordered fast food from a computer for the first time. A jack in the box I went to had a bonus two tacos for anyone who used the machine.

It was a pain. I had to hit a whole bunch more buttons because they kept trying to get me to upgrade in some expensive way or another. Still, once made less annoying, or even if not made less annoying, I have little doubt that it will become common place. The fact of the matter is that machine probably costs less than a year of a minimum wage labor. I strongly suspect that over the next twenty years fast food restaurants will slowly transform into high tech vending machines. There will probably be one person there to watch over things, much like most gas stations, but that is about it.

I must admit to getting worried that we won't have enough jobs. The only thing that gives me hope is that we have so many useful things we could be paying people to do. They could be returning the Los Angeles River to an attractive state, building a StarTram, teaching English to immigrants, fixing the absurd numbers of potholes in roads, cleaning up all the trash that makes downtown LA so ugly and so on. Still, neither private industry nor government seem to actually be hiring people to do these things.

Thursday, September 15, 2011


I know a few government contractors. They all seem to make many times as much money as actual government employees.

Looks like that isn't just my small sample size. Sure enough, private contractors are more expensive than government workers in a wide variety of fields. This shouldn't be surprising. Government workers get part of their benefits as really secure jobs. Therefore you would expect them to be willing to work for less.

I have become pretty skeptical about contracting out work in general. Some utilities have gone as far as contracting out almost all engineering. Of course, what is the inevitable outcome of this? Yes, if no one at your company understands what they own than sooner or later you get held hostage. Employees might not be all that loyal, but they at least think of themselves as on the same team as other people at the company. Contractors are much more likely to have a mindset of taking the company for all it is worth. There is a place for it of course, but only for work where you do so little of it that you cannot afford enough full time people to get the necessary economies of scale to do the work efficiently.

Thursday, September 8, 2011

Have we stopped cowering in fear yet?

The ten year anniversary of September 11th seems to be bringing out a whole bunch of articles which are pointing out the obvious absurdity of spending a trillion dollars to save what might be a couple thousand lives, but given how few terrorist attacks we have stopped from government action may well be no lives at all.

Does this mean we can stop cowering in fear over an unorganized bunch of thugs who seem to only be able to pull off an attack on American soil every decade or so?

Here are a few of these articles:

Businessweek, Slate. The Atlantic, LA Times, SF Gate.

Jerry Brown has earned my respect

I never really knew much about Jerry Brown. About the only thing I really knew about him was that he seemed more sane than the Republican he ran against.

I am starting to think I like the man though. He recently vetoed two bills which makes me respect him a whole lot more.

He vetoed a ski helmet law a few days ago with this comment:
"While I appreciate the value of wearing a ski helmet, I am concerned about the continuing and seemingly inexorable transfer of authority from parents to the state. Not every human problem deserves a law."
And vetoed a phone fine bill with this comment:
"I certainly support discouraging cell phone use while driving a car, but not ratcheting up the penalties as prescribed by this bill. For people of ordinary means, current fines and penalty assessments should be sufficient deterrent."
They still allow politicians to say things like this? I thought this was the sort of thing only Republicans would spout in between shouting that the war on drugs and the war on terror means you should give up all rights and let the Federal government run your life. The democrat party needs to come up with a few hundred politicians willing to take stands like this. Maybe then we can get our priorities in order.

Monday, September 5, 2011

An upgraded simple three phase generator design.

After my failed attempt at getting an output I deemed acceptable out of the simple three phase generator I built I went ahead with a redesign. Instead of four large disc magnets, I used 8 smaller block magnets. Instead of six 500 turn coils I used twelve 200 turn coils. Once again I used 30 gauge magnet wire.

This generator becomes a rats nest of wires and is therefore less simple than the previous version. Still, it can be constructed fairly cheaply without expensive tools.

The first step was to wrap the coils. This time I wanted coils just barely larger than the magnets which would be rotating. Therefore I decided to wrap wire around the magnets. It is very important to wrap the wire in the same direction for every coil, and remember which way they are. If you flip the rotation on the coils, it will dramatically lower the output of the generator, perhaps even to no output at all.

After making 200 turns around the magnet I did one more turn where I wrapped the wire around the coil to hold the wire in place.

Once all twelve coils were constructed, I mounted them on a CD with super glue. This is the step you need to be careful that all are placed in the same orientation. If you install some upside down wiring the generator will become a real mess. It is also important that all the coils are evenly distributed. One coil should be at 0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, and 330 degrees. Here is them just before I glued them.

Positioning the magnets was done on a saw blade this time, rather than the CD used in the design I based this on. This is for two reasons. The saw blade being steel acts as a backing iron and helps direct the magnetic fields through the coils it also is a little easier to rotate than the CD. I assume this generator would work with a CD, but would produce a little less power.

Similar to the toys from trash design a large washer was glued to the top and bottom of the hole in the center of the saw. A toothpaste cap with a hole drilled in it was glued to the top of the rotor. The magnets were placed at 0, 45, 90, 135, 180, 225, 270 and 315 degrees which was made easier by the holes in the saw blade. Once positioned they were glued in place, although I am not sure that was necessary with how strong the force between the magnets and saw was.

As before the magnets must alternate. The magnets at 0, 90, 180, 270 degrees will all have north pole facing up when the magnets at 45, 135, 225 and 315 degrees are all have north pole facing down.

This time instead of iron filings, which were quite a bit of work to collect, I decided to use steel wool for the cores of the generator. I simply cut up the steel wool into small pieces then mixed it with wood glue before filling the cores with it. This didn't seem to be quite as good as the filings, but it clearly performs the basic task.

The next step was wiring, which requires some thinking. A good description of the theory of wiring such generators can be found here. For this generator it was necessary to connect 4 coils together to make each phase. The coils at 0. 90, 180, and 270 degrees make up one phase; the second phase consists of the coils at 30, 120, 210, and 300 degrees; while the third is made from the coils at 60, 150, 240 and 330 degrees.

The coils must be connected together so the current adds rather than subtracts. First for each magnet you connect the low side of one coil to the high side of the coil on the opposite side. which side you declare to be low is arbitrary. I decided I wanted the right side wire on each coil to be low. Once you have connected each with the opposing coil, you need to connect the low side of one group with the high side of the group perpendicular to it.

I made some simple sketches showing the wiring, first of one phase, then of all three phases combined. Notice that the low side of all three phases gets connected together. That is where neutral connections are made. This makes it a typical Y connected generator, leaving me with three phases neutral. I could have done a delta connection but I wanted to have the neutral.

This time I decided not to use the sewing machine bobbin for a rotor. It just allowed too much wobble, making it too difficult to get the distance between the magnets and the coils as small as possible. So, I decided to glue a nut and washer together. I then placed additional nuts and washers in place to adjust the height. The rotor then simply rotated on a washer which I lubricated with WD40.

This generator worked a better than the previous version. It produces about 1 Volt phase to neutral, and 1.7 Volts phase to phase. I can light LEDs by connecting an it to any 2 of the four wires.

Still, the rotor could be a lot better. Two washers rubbing against each other do not exactly make the most efficient bearing. I will be keeping an eye out for a way to mount the rotor in a lower friction manner.
Another step which could be done to improve the generator is a backing iron on the coils. So far I just haven't found an easy way to modify this design to allow that. Unlike the backing iron for the rotor, the backing iron for the coils cannot be solid iron. Doing so would create eddy currents which sap the efficiency of the motor. So I would need to make a laminated steel or iron filing based replacement for the bottom CD. Nothing simple comes immediately to mind.

A failed upgrade to the three phase generator

After I created a three phase generator, my first thoughts were about how could I upgrade it to increase the power. Ideally I wanted a generator which could produce three phase power at a low enough frequency that I could see the A B C phase rotation in real time on LEDs.

The most obvious way I could upgrade my generator was with a iron core. The iron in the core gets magnetized whenever a magnet passes by. This dramatically increases the magnetic flux through the core and therefore increases the voltage produced by the generator. The best material for such a core is laminated steel. This is complicated and expensive if you don't have the tooling. So I followed another DIY generator page and used iron filings for a core.

The first thing I tried was to go into my side yard with a magnet. This failed. The soil was too hard for me to get any significant number of filings from it.

Next, I tried to destroy an old rusty pan with a file. This worked, but was way too much work. I then tried drilling a whole bunch of holes in the pan with a drill. This also worked, but also was too much work. There just isn't as much steel in a muffin pan as you would expect.

Next, I tied two large neodymium magnets to a string and went for a walk dragging the magnet around. Eventually, I found a big area with loose dirt next to a road. This was just full of iron filings and in ten or fifteen minutes I was ab to get what I needed.

After getting home, I cleaned the filings by dumping them on the ground and picking them back up until I got the dirt out of them.

Then I mixed the filings with wood glue and filled my cores with the sticky mess.

I then put the rotor on the generator and tried to spin it. Nothing. Not that it didn't produce any Voltage, but it didn't spin. The magnets were so strong that they bent the cd pulling all the magnets right up to the core. The rotor was just not strong enough to spin them.

I thought I could fix this with a stronger rotor. So I went and bought a 4.5 inch saw blade and mounted the magnets on it. This failed too. Instead of the top CD bending, the bottom CD bent.

I tried gluing the bottom cd to the acrylic plate. Still, no luck. The magnets could rotate if I got them high enough, but not fast enough to produce a reasonable voltage.

The last thing I did was put 8 smaller magnets on it. I couldn't rotate unless the magnets were well above the cores, but finally I got a volt out of the generator. I was still not all that happy with the output though. So I went ahead with a redesign of the generator.

Sunday, September 4, 2011

A simple three phase generator

About two years ago, I built a simple generator. It was just about as simple a generator as is possible to produce a box, a coil of wire, four large magnets, and a nail to rotate them on. This has been sitting in my office for some time and makes a really good demonstration. Even many people with a strong electrical engineering background seem to have never really understood what was going on in generators.

So I decided to take the next step. The generators on the power system are three phase generators with some having a forth wire for a neutral. Having essentially no tools, I started to look around the internet for DIY plans I could use to make one. This one caught my attention. It is really simple requires no special tools to make but is not a three phase generator. However I realized that I could modify the basic design to make a three phase generator.

By increasing the number of coils from 5 to 6, you get six phases where any two coils on opposite sides are in phase with each other. All that must be done to make a three phase Y connected generator is connect together opposite sides then connect one end of each group of coils together to make the neutral. The wiring of this sort of pancake generator is best explained at this site.

Once I assembled the materials, the first step was to create the six 500 turn coils of 30 gauge magnet wire which are required. I found that wrapping the magnet wire around a film bottle made acceptable, if a bit messy, coils:

Once I got to the end of wrapping the coils, I did one more turn where I wrapped the wire around the coil to keep it from falling apart. Here is the final set of coils I constructed:

These coils were then mounted on a CD with superglue. Spacing between coils was kept even so that the coils on opposite sides would have current in phase to each other.

The rotor I used was mostly the same as that in the generator project I mentioned before. Magnets were glued to a CD at 0, 90, 180, and 270 degrees. The magnets flipped orientation so magnets on opposite sides were pointing the same direction. A toothpaste lid was glued to the top, a large washer was glued to the bottom.

The components were connected together as in the toys from trash design, except for an acrylic sheet being used to substitute for the wooden block the bottom CD is . I also put some washers on the back of the magnets to make a crude backing iron.

Once everything was connected together, opposite side coils were connected together. You have to be a little careful about getting the two sides to be in phase with each other. Assuming the coils are in the same orientation, opposite side wires should be connected together. I was fortunately careful to keep the alignment constant so this was straight forward. If one coil was wound in the opposite direction than the wiring must be reversed.

One phase of each coil on one half of the CD were then connected together. This left the generator with three phases on one half of the generator and a neutral which connects on the other half of the generator. A classic Y configuration.

After connecting together all components, I spun up the generator. It would produce 0.3 Volts phase to ground AC and 0.5 Volts phase to phase. Theoretically, this generator should produce 1.732 times as much phase to phase voltage as phase to ground voltage. This was close enough to convince me I set everything up correctly.

Overall, I was pretty happy with this generator. I managed to produce a three phase generator with about $20 in components and no tools beyond a soldering iron and wire cutters. After looking around online for a while, I believe that this is the simplest three phase generator design out there. Because of this, you can really get an idea of what is happening in the black box that is the usual generator. For example when you are thinking abstractly of phases, the idea that A phase leads B, leads C can be difficult to understand. When you actually see the magnet reach A phase, then B phase, then C phase it starts to make more sense.

The disadvantage of this generator is that it really cannot do anything. If you spin really hard you can make a LED blink a little bit. Unlike the simple one phase generator I made it isn't easy though. I was hoping to make a simple straight forward 3 phase motor to go with this generator. I didn't even try. it isn't much good for powering anything but a volt meter. To try and eliminate these problems, I altered the design to include iron cores. This created other problems though.