acvoltage
If AC voltage is alternative, why there are two (Suppose there is no earth wire) wires attached to the wall socket: live or hot, neutral wires? And I think that in small home generators there is no need to specify which wire is the live wire?
I've read that the neutral wire is connected to the ground. Where it's connected, I mean at the house or somewhere else ?
Yes it is an single phase motor, referring to the wire color codings. You need to step up transformer 110/240 but before you do so u need to check the frequency. As in Europe its 50 Hz not 60 Hz as this may effect your motor's speed.Please refer to the picture below link: 
Is it safe/functional to keep the Earth and Neutral terminals connected from the power supply to the AC/DC converted while switching on and off the Live wire?
Yes. Not only is this safe, but it's the standard.
Switching neutral is dangerous: if the live side of the switch fails closed, parts of the device may be energized to line voltage while the device is switched off. If the device is plugged into other powered devices, it may even end up powering itself through the other device's ground.
Best Answer
There must be two wires for a complete circuit.
Now, in a balanced AC circuit, both wires provide an alternating voltage with respect to ground (earth). When one wire is positive, the other is negative.
However, in an unbalanced system, one wire is neutral, which should ideally be at 0V with respect to ground, and the other is hot which alternates positive and negative with respect to ground.
In either case, both wires have (ideally) equal and opposite current.
If I'm not mistaken, in the USA, the neutral and ground are connected together at the meter base (service entrance).
For a generator that isn't referenced to ground, the AC voltage is simply across the 'hot' and 'neutral'.
There are devices for converting unbalanced AC to balanced AC power.