Can a wife claim alimony for a minor son

Yes, but its not called alimony. Its maintenance share for the child.

Yes, u can claim maintenance amount for ur son from his father. For further detail and any query u may call at 9871158578

One more thing a Wife can claim maintenance for  Major Son as Both son as well as she himself is working somewhere.

Please tell me. 

What is the maintenance fee that can be claimed for the son in case wife is earning, without applying for divorce?

That depends upon :1. Status of the parties 2. earning capacity of the parents and 3. the needs of the child according to his social status.  After considering all the factors the court will come to certain amount shall be maintenance amount for the child and it will be divided between the mother and father according to their earnings.  If mother is earning 50 thousand and father is earning 1 lac and the child's maintenance is quantified  10 thousand, then mother has to incur 1/3rd and the father has to incur 2/3rd.

As we are living in patriarchal society, the court inclines to opine that father has more financial responsibility for the maintenance of child and hence divide the ten thousand in equal shares and ask the husband to contributed about Rs.5000/-, even their earning capacity is varied.