There will be no, or negligible braking effect. This is because when disconnected from the AC mains supply there will be no current in the stator and residual magnetism will only induce a very low current. You can test this by pulling the AC mains plug when the saw is running and shorting L and N on the plug. I expect there will be a very slight braking effect, but the saw blade will still keep spinning for a long time. The only way to achieve a rapid stop is by DC injection braking.so after I turn off the saw I can press and hold in the button in to slow the blade faster?