About the alternator

http://en.wikipedia.org/wiki/Alternator might suggest that very little power comes out of it.

Your waveform will look like a worm in hot coals.

John

Your output frequency will be modulated by the AC. If you rectify it you will still get DC. However, the field pole material may not be designed for AC and so you may get extra heating from eddy currents.

Sorry. But that is nonsense.

Here's another good one. Pull the plug wires in your car. Put them back randomly without regard to firing order. While you are at it you may as well pull the distrubutor and then put it back at some unknown angle. Start your engine!

John

Oooh, I am so interested in your highly articulate critique! Please explain in technical terms why this is nonsense so I may critique your lack of understanding. Seems to me that the output will be a product of the angular velocity of the rotor and the instantaneous amplitude of the current in the field coils. I never said to try it on your car but since we don't know what the fellow had in mind I simply described what would happen. Please, if you can, tell us more about what you think will happen!

My apologies for my casual wording. It is certainly not the output frequency that will be modulated but the amplitude of the AC output waveform.

Sunil,

on a practical basis, you would probably end up destroying things! Theoretically, you might have a motor, but only theoretically, believe me.

A good alternator does not make a good motor and there are bits in them (diodes etc) that are simply not needed as a motor!!!!!

The construction as a whole would probably get too hot, efficiency would be low even if altered correctly and you might even get injured....

Motors are also cheaper to buy than Alternators in the first place!!!

Think about something more useful and productive.....and have a great day.......

The field in alternator requires a basic north and south pole magnet, this can be either a permanent magnet which cannot be varied or an electro magnet magnet which can be varied to adjust the output.

The alternating rotary cycling of the north and south pole produces the AC sinusoidal output wave with a zero mid cycle and equal positive and minus peaks.

Injecting AC into the field will result in the magnet vibrating and reversing at the AC frequency.

As somebody said earlier this will superpose the field AC frequency upon the AC output of the alternator which will require far more complex rectification to achieve a final DC output.

If you do not have DC available and you are not using a DC output, then it is far simpler to rectify the AC input the field and that solves all the problems.

If it's a 2 pole alternator, speed of prime mover will be 3600 rpm. Here we are supplying with ac field with 60 Hz, so nos. of poles will be 60.

Is there any chance this may results into output power frequency = P-N/120 = 60 * 3600 / 120 = 1800rpm ?