Induction Motor/generator

Hi
Are there any real differences between an induction motor (3 phase squirrel cage) and an induction generator (where the reactive power is supplied by the grid), i.e. are the windings or rotor changed in any way?

induction generator

Hi,
I have conected an induction motor/generator to the UK mains (230v 50hz) and my waterwheel.
THe motor is 4hp 3phase 400v delta. I have connected one winding only to mains so I expect maximum output =4hp/3/(230/400).
When there is no water flowing over the wheel (ie the motor is totally a motor, powering the wheel) the current drawn is 2.5amps.
On increasing the flow over the wheel the current drops to 1.6 amps and then starts to increase.
I have taken it up to 7 amps (for a short time only)
The indicator on the electric meter which shows reverse current is lit, showing that power has been fed into the grid.
Questions:
Does the 1.6 amps represent the amount of excitation that has to be drawn in? (seems like a lot)
How much is the generator generating, 7 amps, 5.4 amps orsome different amount?
How do you measure the power produced (poss by having two meters,each measuring in only a single direction?)
Am I right in thinking that the maximum power will be produced at the maximum (positive) slip so that a full load speed of 1415 should run at 1585?
In this case is it a good idea to look for a motor with the smallest amount of slip (and are purpose made ig`s designed with smaller slip value?)

induction motor speed

Hi y`all,
Normally I expect a 50hz induction motor speed to be 1450 to 1480 rpm (nominal 1500). I have one here (230v 1phase, 50hz) which has a run speed of 1350. What would be the reason for this large amount of slip?
Regards

switchable 1 to 3 phase motor?

Hi,
check this ebay item

http://cgi.ebay.co.uk/ELECTRIC-MOTOR-2-5HP...1QQcmdZViewItem

Would this motor have two completely seperate sets of windings or would the 3 phase windings be re-jigged to enable 1 phase start and run? Or is he simply wrong and its purely a 1 phase motor.

Copy of email from seller "Hi, the manufactureres are, melegari l. & figi, type 2-3 motore asincrono m90l n2 l. Sn fe1563, hope that helps, cheers,"

Also says he has run it as 1 phase but has no 3 phase to try out.
Regards

induction motor/generator

Hi,
If I connected one coil of a 3 phase 400v motor to single phase 230v and externally powered it (e.g. with a waterwheel) up to sync speed + then it should act as a generator and send out power on all 3 phases (though two of these will not have much oomph). Correct?
So what would happen if all three phases were connected in paralell to the same single phase mains line? Would the coils act in sync and be in effect a single phase motor/generator? Or would it still try to generate in 3 phases and end up with a very strange waveform and, in short order, a burnt out motor?
Regards