The problems are very considerable.
You will not adapt the hugh Piggot types of design to electromagnet. The large air gaps mean that the field current would be so high that you would get nothing out.
You will need slotted iron cores with small air gaps, That effectively means modifying vehicle alternators or converting induction motors to wound field.
You will need machining facilities to make replacement rotors for induction motors.
Don't expect much in the way of low wind performance, if you are in a windy area you could do quite well.
Unless you have full workshop facilities you had better stick with large vehicle alternators and rewind for lower speed, results will be not very inspiring but you can make it work.
Probably the best compromise would be a good motor conversion with neo magnets, you will need less than for an axial air gap alternator. Performance in low winds will almost certainly be better than with a wound field unless you are very clever with trick than can make a wound field machine fairly reasonable.
flux
