Sep 05
admineOrbo replication 2 Orbo, Steorn
While waiting for the milling machine parts I finished one core. It was wound with a double 0.25 mm wire. I can choose to connect the two windongs in series, parallel or use only one of them. When finished I checked for shorts between the wire and the core. All you need is a multimeter to check that the resistance between the wire and the core is infinite. I happened to use an LCR meter. One lead was connected to the magnet wire and the other to a knife. I used the knife to cut into the edge of the core between the turns of the coil. Make sure the knife does not touch the wire because it will easily cut through the enamel and give a false reading.
Checking the finished coil
Aug 30
admineOrbo replication 2 Orbo, Steorn
I have tried different methods to ensure the enamel of the magnet wire will not be cut by the sharp edges of the Magamp/Nanoperm cores. The only good method I have come up with is LDPE. In my country disposable shopping bags are made from LDPE. The average shopping bag is 30 -35 micrometers thick, but I tend to use the thickest I can find. I cut a a 4-5 millimeters wide strip and wind it on the core. Each turn overlaps half the previous turn. I don’t know why LDPE works, but it does – every time (knock on wood).
Cores protected by LDPE
In many other countries disposable shopping bags are made from HDPE which is thinner. This is the kind of shopping bag that makes noise when you handle it. I have not tested it, but maybe whatever makes a good shopping bag can be used?
Aug 29
admineOrbo replication 2 Orbo, Steorn
Time to start working again. I have prepared four sets of cores to be tested with the rotor I will let the Profiler mill for me. One set is Magnetec Nanoperm cores, two are Metglas Magamp and the last is plain old Ferroxcube ferrite. The cores, except the ferrite cores, have been prepared the following way:
- The cores have been removed from the plastic casing and cleaned.
- To make the cores stiff I placed them on a table and placed small drops of super glue gel on the side. With a piece of scotch tape on the finger the drops were distributed evenly on the surface. The procedure were repeated on the other side. The thin Magamp cores were treated this way two times on each side.
- To protect the very thin and brittle metal the cores were coated with polyurethane floor varnish.
four sets of cores
The most difficult problem with these cores is that the sharp corners will cut through the enamel on the wire and create a short circuit to the core. One step remains before it is safe to wind the coils. More about that next time.
Jun 29
admineOrbo replication 2 Orbo, Steorn, Stoern
I have finally received some MAGAMP cores. Two different sizes, 11 cores in all. Can’t say it was easy as it took 6 weeks and several friendly reminders before the seller finally sent them. They will of course be tested in the eOrbo replication, but that project will delayed about 3 months and I will therefore do some other experiments with thee cores in the mean time. It is unlikely I will share these experiments with the public at this time.
Jun 23
admineOrbo replication 2 Orbo, Steorn
I found that the stepper motor for the x axis has an internal short to its metal body and this most certainly disturbs the driver circuit. I have contacted Colinbus support for their opinion and expect a reply tomorrow. It usually takes two workdays for them to reply. I hope I finally found the source of my problems and that a new stepper motor will be the fix. However, this will take time and the next window of opportunity to use the milling machine is in September or so I hope. Oh well, there is a lot of other work to be done at home and now I have no excuse not to do some at least some of it.
Jun 21
admineOrbo replication 2 Orbo, Steorn
Yesterday I took the machine apart to adjust the x, y and z axes. This is finished and I found that two ball bearings need to be replaced. After assembling the machine again it would not start. This threw me off balance and I needed to find a quiet place for some moments. Eventually I disconnected the three stepper motors from the drivers and reconnected them one at a time. It worked, but I don’t know why. It is an indication that I have an electrical problem somewhere. When the machine was running again I was touching the bare metal of the machine and noticed a tingling sensation in my fingers whenever the x axis was running. (I am extremely sensitive to this and often feel this tingling when touching a wire from a USB port.) It is interesting to note that the random moves always happen on the very same x axis.
Jun 20
admineOrbo replication 2 Orbo, Steorn
This is so frustrating. With the new controller the milling machine sometimes has its own mind. Suddenly it moves to a position it should not have moved to and I have to start over. Cutting through 10mm Lexan is done 0.5mm or 1mm at a time and if the random move happens when the cutter is 9mm into the Lexan the cutter grinds to a smoking halt putting a tremendous load on the machine, the spindle motor and the cutter. Now the Z-axis is out of adjustment and the cutter is bent (or maybe it is the spindle motor). In a last attempt I will reinstall the old controller, try to adjust the machine and try again. Time is running out.
Jun 13
admineOrbo replication 2 Orbo, Steorn
Finally I have received and installed the new 3D controller for the Profiler milling machine. Then I wrote a test file with G-codes, but it didn’t work right away. Seems that the controller takes feed rate as mm/sec, but the control program (ColiDrive) expects mm/min in files. I have contacted Colinbus support asking for a file format specification. I have also readjusted the Z-axis – everybody say it’s a bitch to do it and it really is. Now I believe it is as good as it can be and the nNext step will be to start milling….
Jun 01
admineOrbo replication 2 Orbo, Steorn
I went to a local glass shop today to get some Lexan. The pieces I need are relatively small and they had leftovers I got at a reduced price. I guess they knocked off 70-75 % which I really appreciate because Lexan is expensive. Plexiglas is less expensive, but not an option because it melts in the milling machine. If I can find the best milling bit, spindle speed and feed rate for the job I am quite sure the melting can be avoided. Lexan can also be difficult to mill, but I have found a way that works.
Yesterday I ordered and paid for a new 3D controller board for the Colinbus Profiler milling machine. This will replace the 2.5D controller board currently in the machine. As I said earlier there is a problem with the machine and it was either necessary to repair the 2.5D controller or upgrade to a 3D controller. The new controller can read G-code, it can be configured by software and I believe it can be flashed when there is a new firmware release.
May 30
admineOrbo replication 2 Orbo, Steorn
Yesterday’s post was a mistake. The hall switch is sensitive to a single magnetic pole on one side and to the opposite pole on the other side. I knew this and at the moment I was thinking that if the sensor didn’t sense I could just move it to the other pole. That is correct only if the same side of the hall switch is facing the other pole. This was not the case yesterday. I was lazy and didn’t think when I just moved the sensor around. The way to do it is to turn the sensor because it will work every time and does not depend on the situation at hand.
With my rotor the magnetic field is shooting up and down and not radially out the where the toroids are placed. This is not optimal, but having pockets in the rotor is attractive seen from an experimenter’s point of view. I can easily play with different size magnets just to see what happens. This may or may not be the best way to replicate eOrbo. It is, however, a good way to learn more.
The motor was started with a single toroid and with strong enough magnets the acceleration is good. I like running it with a load and the load this time was fan blades. It accelerated to around 3000 RPM. In my first replication the load was the fan motor (converted to a generator) and I used two toroids. This means the two replications cannot be compared at this time.
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