søndag den 17. oktober 2021 kl. 23.26.51 UTC+2 skrev Joe Gwinn:
but that board is for RC servos, which is nothing like a fan
but then you don't need that board because it is just a bunch of pwms to control a large number of RC servos
What's wrong with the traditional, series inductor to reduce speed?
It doesn't change the frequency. Synchronous motors spin slower if they are driven from a lower frequency source. Induction motors lag the rotating field but they won't rotate if field rotates much faster than the rotor can spin.
Several reasons; the turntable wow and flutter are treated by using slippy motors, and heavy tables, for mechanical filtering of any AC deviations. You have to do that part of the design with known motor torque info. It's deadly too, to have harmonics making the motor hum or buzz; critical listening is going to happen while the vinyl is spinning.
Ah, but fan motors are productive if they're off-frequency, while turntables aren't. In a fan motor, you want energy efficiency after startup, and noisemaking is acceptable. In a phonograph, not so.
Don't tell me, tell phil.
buzzing fan motors are not acceptable, and it's not hard to make some of them sing, usually the cheaper ones running at the limits of not catching on fire due to all the removed copper and iron.
Good grief! Start with a fan that produces the maximum required flow, so that you don't need to change the frequency It's 100+ year old technology. Even you should be able to understand that much.
Some people object to a fan that is noisier than it needs to be. By being able to adjust the speed of rotation to match the heat being generated you can minimise the irritation.
There's lot of 100+ year old technology that can be brought into play, but you and Phil Allison don't seem to understand it as well as you should.
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