Some photos of the motor and separately the data plate would be very helpful here. I think I asked this the last time you were trying to sort this out. Knowing whether this is a braked motor or not would be a start (I have the 20" Jet which does have a braked motor but don't know whether the 16" and 18" ones do) since this makes a big difference to the price of a replacement motor. It could also be part of this cause for burning out the motor you have (if braked).
A 1.5hp motor is going to be 1.1kW so an 80 frame 4 pole flange mount motor has a 19mm shaft so photos would help confirm whether it is flange or face mount. This is for a non-braked, cap start, cap run motor from bearingboys.co.uk
Bearingboys, got the same pic as i posted plus about 6 others, including one showing the shaft length, diameter, keys slot etc, and it was them who quote £658 inc vat for a like for like replacement, becuase according to them it was a special to order from TEC to get a 19mm shaft.