Got a 30 yr old large squirrel cage fan (fan turbine about 15" diam) with a 10" pulley on its axle. The motor has a 2" pulley. I understand motor/pulley is engineered to match the fan specs, so that the motor doesn't burn up.

I'd like to change the motor's pulley to a 2.5" or 3", for the fan to blow more volume of air.... and/or blow it faster.

I suppose I don't need specific math specs/calculations for an answer.... just a good common sense guess at it.

What's the likelyhood of burning the motor, if I enlarge its pulley to a 2.5" or 3"?

I have several salvaged motors, so I may have an appropriate replacement motor, if need be. With a 3" pulley, might I need a motor with more HP and/or less/same RPMs, as the present motor?

I don't have the motor in front of me, to give its HP or RPM specs. Would this info help?

Thanks.
Sonny