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| A generator for Elmer. |
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| modeldozer:
Hi John, Tank you for the kind words. If you look at the lower right hand of the video the light bulb is powered from the generator, I have to use an external dc source to excite the fields. Cheers. Abraham |
| DavidA:
Abraham, looks very good indeed. Couldn't you switch from external excitation to self excitation once the generator is running ? Dave, |
| John Rudd:
--- Quote from: DavidA on February 21, 2016, 03:51:24 PM ---Abraham, looks very good indeed. Couldn't you switch from external excitation to self excitation once the generator is running ? Dave, --- End quote --- I had thought of that, but given he is reading around 5v on the dvm, I dont think it will be enough..... Given that the field coils are wound for 220v....less turns with thicker wire might work... Abraham, how fast is the rotor turning? how much voltage are you applying to the field coils? |
| modeldozer:
Hi Dave and John, Like John said, it does not generate enough power to self excite, have even tried adding some small magnets. My only other thought is, if i can find suitable magnets, to replace the fields. Experimented a bit with the voltage and current and in the video was using 5V at around 2A. At 12V the current goes up to around 3.5A but the coils start to get hot. The field coils have a resistance of 2ohm. The rotor was turning at 1800 RPM. Any advice is greatly appreciated. Cheers. Abraham |
| John Rudd:
I'm no guru, but it would appear that the dc resistance of the field is too low. Ordinarily the current through the coils would be alternating due to the commutating action of the rotor commutator..... Rewinding the rotor with thinner gauge wire and more turns would probably improve things whereby you could externally excite it.....conversely, rewinding the rotor with thicker wire and less turns will increase the output, Hmmmm that doesnt sound right that bit.... I 'd try the field first, keep the rotor as is run it at the same speed.... |
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