Lew Hodgett wrote:

Somebody wrote:

A modification can be made to table saws with induction or split
phase motors. You change the power switch from SPST to SPDT, add a
diode & electrolytic capacitor that charges when the motor is
running.
When you switch the motor off, the capacitor discharges through the
motor, causing a rapid braking effect. This can't be done with
universal motors, since they will run on DC.
----------------------------------------------------------------
Otherwise known as dynamic braking.

Usually involves a DC power supply and a mechanically interlocked
motor starter and a DC contactor along with a time delay relay.

Normally used on three phase motors and requires a motor designed
for the application.

Will usually rip the stator out of the housing of a standard NEMA,
Design B motor without additional pegging.

An expensive solution at best, have never seen one on a single phase
motor, doubt a capacitor large enough to stop a single phase load
would even come close to offering a cost effective solution.


You are ignoring the field inductance and that it doesn't discharge
the cap instantly. You don't need to stop it in a fraction of a turn,
but the DC can slow it to a stop in a fraction of a second without
damaging the motor. The motor comes up to full speed in that same time
frame. I;ve seen construction progects about adding braking to existing
power tools, but no longer have them.