Yahoo Q & A
- Why does a steel becomes permanent magnet even though the current in the coil is cut off?
First of all, you have asked the wrong question, which gives the wrong answers. Residual Magnetism supplies answers that are not always correct, depending on the question. The proper question should be "Why does a steel of a rotating electromagnet structured as pole faces become magnetic during rotation?" Then we do not need to ask why the magnetism remains after the current of the electromagnet is removed, because then we can then CANCEL that pre-existant rotating magnetism by sending currents in the OPPOSITE direction on the rotating electromagnet, to finally make the alternator electromagnetic pole face rotation vs stator output come to zero. In this particular case we have supposedly removed the "remanent magnetism" of the field rotor: which is attributed to these unusual effects of obtaining power from an unenergized electromagnet in rotation. However having done this the next identical rotational start-up reveals the same effect attributed to remanent magnetization, and not instead rotational magnetism. In the next test we further increase the field current in the wrong direction so that once again the pre-existant output is reduced to zero, and then with further field current a stator output again appears. Now we then decrease the field current to the former field currents that yeilded zero stator output. Now we find that instead an output is obtained, where formerly none was present from the stator windings at this field current level. The magnetism applied to rotation has been "remembered" so that it responds differently the second time. This is the real aspect of "remanent magnetism preserved by rotation". Once the electromagnetic stops rotating however, nothing is remembered. And even though we have magnetized the steel in an opposite direction then what the rotation itself delivers, or what the remanent magnetism theory pre-supposes as the cause for the effect, on a repeat of the experiment the so called remanant magnetism effect will always agree with the actual direction of spin of the electromagnet.
Can three phases of 120 degree AC be combined in series to yield the sum of their input voltages?
If a full wave rectification is placed across three phases each reading 1 A rms, at the peak of any three AC signals will be 1.4 A, and at that moment in time the remaining phases will be delivering half of this value, or .7A. The combination of these currents for rectification to a common load would then be 2.8A,not counting the diode losses. The amperages existing on the input alternating currents would have been sequentially added for DC application to a common load. Would it then be possible to somehow "sequentially add" three one volt signals from a three phase alternator, to make for a 2.8 volt input application to a high voltage transformer, where the voltages from each phase can be sequentially added together for application to a common load?
Pioneering the Applications of Interphasal Resonances http://tech.groups.yahoo.com/group/teslafy/