to run your lights and accessories and maintain your battery between starts.
Cars don't use generators because the batery is already generating energy. They use alternators in order to convert the energy generated into a usable form.
alternators are classified as stators and rotors
Direct current can be generated by a generator. Generators are not as efficient as alternators ( that generated AC power ). Vehicles use direct current but come equipped with alternators. The AC power is rectified ( changed to DC ) for use.
Firstly, no you must not pick the particular Alternators
Two alternators are used as a safety measure. The probability of both alternator failing are very minimal. Many planes use redundant systems.
This question is not clear since alternators produce alternating current.
Make sure the alternators are properly installed and aligned.
http://www.techsupportforum.com/archive/index.php/t-57498.html
One can research the prices of used alternators by going online and looking up alternators of the right sort on Amazon. There are various different merchants there so they will have various prices.
Yes.
Alternators produce AC, which is rectified by diodes if DC is needed. Dynamos produce DC by using a commutator.
Since the alternators are in parallel, the resultant voltage should be the same as either alternator - exactly as it would be if two batteries are connected in parallel. Voltage remains the same but current capacity is doubled. I would recommend connecting the alternators through a network that will balance the load between them.