To convert watts to horsepower you need to know that 1 horsepower is equal to 746 watts, then:
[tex]2500\text{ watts}\times\frac{1\text{ HP}}{746\text{ watts}}=3.35\text{ HP}[/tex]You also know that the fan requires 2 1/2 HP, which is equal to:
[tex]2\frac{1}{2}=\frac{4}{2}+\frac{1}{2}=\frac{5}{2}=2.5\text{ HP}[/tex]Thus, the motor produces more power than the required to drive the fan. The answer is Yes, it can be used to drive the fan