08-01-2015, 06:37 PM
The two cap motor has both capacitors in parallel when starting and when up to speed the large one is open circuit via the switch centrifugal or electronic switch and the motor continues as cap run. These motors have better starting torque than the cheaper cap start induction run. ABB I'm told, have introduced a range of motors known as CSR which use an electronic starter (Triac) and if the motor cannot accelerate up to normal running speed within 2 seconds the thing will switch out (thermal overload), so no good with belt sanders and the like. No doubt they are cheaper than the mechanical centrifugal switch and should easier to change should one go wrong and it doesn't need a motor to be dismantled either as when a mechanical switch sticks open or contacts welds up.
