Can anyone explain how electic brake works?

[Bob]

Hi.

I just had a problem with my Dewalt chop saw (DW705). At first, I noticed the brake was not catching all the time when I released the switch. Then, a little while later the saw just quit working. So, I pulled out the brushes and cleaned them up (I have been doing alot of MDF cutting) and then the saw started working again. After a little while, it stopped working again. So, off I went to get two new brushes. Installed them and the saw is back up and running great. But now, there is no electric brake at all. I am wondering if I installed the brushes wrong or if something else needs to be replaced.

Can anyone explain how these brakes work, and what would cause it to stop working?

thanks in advance. bob

[Wood Butcher]

Check the switch and it's wiring first. Some brakes work by shorting the brushes together(with the power completely removed from both of them). Some also add a very low value resistor to the shorting path so that it is not truly a dead short. The switch is the common element with this method and it is usually the faulty part.

Other braking mechanisms are mechanical.

Art

[lucky4fingers]

Mine had the same problem the blade was loose. VERY VERY scary. The brake worked again after the blade was tightened.