[mill (Martin)]

If the gears fit then it would be ok.
A 12V dc powersupply should work as long as it is properly regulated, so not an el cheapo one.
With that i mean: the cheap ones can output between 12V and 18V dc and have a lot of ac on top of that because there will be only a bridge rectifier in it and if you are lucky an capacitor.
The more expensive ones should have a proper voltage regulator in them and will output 12Volts at all time give or take 0.5V (depends on the load).
But for that price you could also buy a 12V 12Ah rechargable battery from Jaycar or Dick Smith for about $30.00
The only thing with batteries is that they have to be charged, so if you already have an battery charger then that is the best way to go.
The amperage that an plugpack should deliver would be about 1 to 1.5Amps at 12Volts.