Your explanation is incomplete. First, the practical phase shift is more like 45°, not 90° (if you got anything near 90° by having the resistance of the shading coil very low, the amplitude would be hopelessly weak). Second, no matter what the phase shift is, adding 2 sinewaves will ALWAYS have 2 zero crossings per cycle. There are 2 things you miss. First, the 2 sinewaves each have their own SEPARATE magnetic paths in the iron, one passing through the shading coil, the other not. THEY ARE NOT ADDED TOGETHER. Secondly, the magnetic force is proportional to the SQUARE of the wave amplitude. So EACH wave is SQUARED, SEPARATELY, then the forces are added together mechanically. The sin² forces are always positive, each becoming zero twice per cycle. But the zero crossings of the 2 phase-shifted waves are misaligned in time, causing there to be a positive pulling force that NEVER becomes zero.
It would be good to mention how the magnetic fields for the shaded and non-shaded pole portions do not occur at the same physical location and the armature is attracted to the core irrespective of the direction of the magnetic flux. It is the attractive forces on the armature that add. Explaining WHY the magnetic flux at the shaded pole lags the flux at the non-shaded pole by 90° (induced current in the shorting ring producing its own magnetic flux) would also be helpful.
adding 2 sinusoids with the same frequency WILL ALWAYS YIELD ANOTHER SINUSOID. MEANING THERE WILL BE ZERO CROSSINGS STILL, just happening at a different time. please come back with a better explanation.
So a shading coil can still be faulty even if it's not broken when you look at it? Chattering can be fixed by changing the coil even if it's not physically broken?
I get that with the 2 sine waves neither are both at 0 at the same time, but aren't there still points where the sum of the 2 waves is 0? For example between the 2 points you circled the sum goes from positive to negative, so at some point between it must have been exactly 0. Why isn't there chattering at those points?
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Your explanation is incomplete. First, the practical phase shift is more like 45°, not 90° (if you got anything near 90° by having the resistance of the shading coil very low, the amplitude would be hopelessly weak). Second, no matter what the phase shift is, adding 2 sinewaves will ALWAYS have 2 zero crossings per cycle. There are 2 things you miss. First, the 2 sinewaves each have their own SEPARATE magnetic paths in the iron, one passing through the shading coil, the other not. THEY ARE NOT ADDED TOGETHER. Secondly, the magnetic force is proportional to the SQUARE of the wave amplitude. So EACH wave is SQUARED, SEPARATELY, then the forces are added together mechanically. The sin² forces are always positive, each becoming zero twice per cycle. But the zero crossings of the 2 phase-shifted waves are misaligned in time, causing there to be a positive pulling force that NEVER becomes zero.
It would be good to mention how the magnetic fields for the shaded and non-shaded pole portions do not occur at the same physical location and the armature is attracted to the core irrespective of the direction of the magnetic flux. It is the attractive forces on the armature that add. Explaining WHY the magnetic flux at the shaded pole lags the flux at the non-shaded pole by 90° (induced current in the shorting ring producing its own magnetic flux) would also be helpful.
adding 2 sinusoids with the same frequency WILL ALWAYS YIELD ANOTHER SINUSOID. MEANING THERE WILL BE ZERO CROSSINGS STILL, just happening at a different time.
please come back with a better explanation.
So a shading coil can still be faulty even if it's not broken when you look at it? Chattering can be fixed by changing the coil even if it's not physically broken?
Great videos but could you show the interior of the contactor with the shading coil installed at 90 degrees so we could see how that would look?
I'll add it to my list!
I get that with the 2 sine waves neither are both at 0 at the same time, but aren't there still points where the sum of the 2 waves is 0? For example between the 2 points you circled the sum goes from positive to negative, so at some point between it must have been exactly 0. Why isn't there chattering at those points?
Excelente video bien explicado y entendible. Gracias
Well done sir
A very helpful video. Thank you.
Thanks
Thanks for the appreciation! Glad the videos help!
Simple and elegant explaination
Awsome
What happen when we apply 2phase across coil
Without shaded ring
Just what I needed , a brief and precise explanation. I would have named the video how/why ac relays work.