Doug did something similar to my Vertex a few years back and with the same great customer service. Fixed it free and shipped it back free. I'm going on 8+ years now. Torque on a spinner is much more important than horsepower. I still can't slow mine down with fairly firm pressure. To say I've gotten my money's worth from it is a major understatement.
Charlest, HP is directly equated to torgue in a motor
you will benefit directly from more HP
I built my own spinner with a 3 phase 1/2 hp motor and a single phase - 3 phase freguency drive
has unlimited speed potential settings between 1 rpm to 1800 rpm if so desired
do most of my surface adjustments at 300 rpm with abralon pads and clean n dull