Your problem is not just inrush but turn-off arc quench melting plastic from dry contacts reaching >20kV then arcing in < 1us.
Motor = 2kW @ 220Vac 50Hz
Mechanical switch: two issues
- contact bounce turning on with 5x inrush while speed up, arc power
- contact arc turning off with full RPM back EMF and inertia time.
Inrush= 500% typical of rated current, Ir=2000/220=9.1A
..... = 46A (rms)
Turn off arc= No load current is about 10% of rated so 200W with inertia time in seconds to reduce speed for arc quench , assume 1 sec thus 200J snubber
- needs arc absorbing snubber RC filter. 220V / 110 Ohm = 2A
- est. triangle power=1/3 of peak = 1/3 of 440W = 150W with AC cap
- but this is expensive using brute force snubbers
Best solution is turn on at Zero cross voltage and turn off at zero-crossing current unless also driven by speed control triac.
Ideal Use a 25A Snubberless Triac with 1A switch
Understand failure modes for all switches
Output triac short circuit occurs with 80% of failures, so a series safety switch is needed.
So you see there is no cheap solution for Dentists.
Simplest is not always cheapest.
use electrical Insulated package or add Mica then add silicon grease