I have a large AC motor, and a small DC one. The DC motor generates electricity for a small light, and I was wondering if an AC motor could do the same. Oh, and by the way, for those of you that say motors can't generate electricity, I know from experience that a DC one in reverse can.
Generally most AC motors do not contain permanent magnets nor do they have separate windings that you could use to initiate a magnetic field. So unless you have an oddball AC motor it will not work for you.
Yes it can, it is not quite as easy as it is with a permanent magnet DC motor, but a squirrel-cage AC induction motor can be used as a generator. Searching the internet for [using ac motor as generator] (without quotes, quotes cuts the number down a lot, but still thousands) got about 21 million hits, must will not be use full, but still...
I think you may be asking for the following (1) Say you have a AC Sychrnous motor with dc excitation in rotor. I think in that case that should be possible (2) I am also aware that when an AC induction sq motor falls into a situation where load runs the motor ( say down hill belt conveyors ) in supersynchronous speed , than the induction motor starts pumping power to the system all the while taking the excitation from the power system. As I understand normally , in electro mechanical electric power generators, we have to provide for following two minimum items (a) Mechanical energy (to be converted to electrical enegry) that turns the shaft. (b) Excitation to arrange for the magnetic flux. Further addition : Sq cage or wound rotor shall behave in similar manner in above situation Still further addition:- With regard to your statement on experience about same machine in Motor Regime and Generator Regime, I think and if I am not wrong, is as below: If an machine is connected to an electrical system and functioning in steady state , than the electrical condition can be represented by (a) Terminal Voltage (b) Excitation Voltage ( or the back EMF) opposing the terminal voltage (c) and the Current due to the difference of voltage restricted by the internal impedance of the machine. (A)In Motor Regime the Terminal Voltage is more than the Excitation voltage (B)In Generator Regime the Excitation Voltage is more than the Terminal Voltage
In electricity generation, an electrical generator is a device that converts mechanical energy to electrical energy. It can be of both types i.e AC and DC.It depends upon the coil and magnet arrangement. DC generators are also called dynamo.