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# Physics/Pmg alternator rpm @ 10hz

Question
Sir i have a 100w pmg alternator 3000rpm 120v Ac 50hz
sir i want to know what is exact rpm and volt of this pmg alternator at 10hz....

You said 10 Hz, and there ate 60 seconds in a minute.  10*60=600 rpm (rotations per minute).  You specified the voltage at 120V, so it must be 50V.  But you also said 50 Hz and 3000 rpm, so there's a difference between the electrical output and the physical rotation?  Or are you specifying a rotation and then asking how the voltage would be different at 10 Hz?  If you're going from 3000 rpm down to 600 rpm, then you're dropping by a factor of 5.  Voltage from a generator depends on the rate of change of the magnetic field in the coils, and therefore that should also drop by a factor of five.  That's 24V of AC output, and it should come out at 10 Hz.

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