Delta 36-220 wood chop saw

[Soundguy]

buddy of mine has one of these and said that the auto blade brake just stopped working.. blade now coasts down when you release the trigger instead of auto braking.

I'm not familiar with this model. does it use an electric engine brake.. or some sort of friction brake?

any ideas?

 

[Steave]

Electric brake. But know anything about working on them.

http://www.mikestools.com/ownersmanuals/DeltaMiterSaws/36-220.pdf

 

[Soundguy]

i'm guessing the switch in the out position actuates the motor brake? anyone confirm that?

if so.. then if part of the switch is bad.. that could be the brake issue? or.. I guess the winding in the motor could be out, etc.. if it is that style..e tc. does it use soemthing like a centrifugal ckt that opens at near stop on the brake?

everywher I see , shows the switch as NLA

any ideas on this failure mode?

obviously unit is not at my shot to test it.. so I'm trying to help the guy diagnose it via email..

 

[Steave]

You're right about the switch probably being bad. That's about all it could be if the motor runs.

With the switch on it sends power to the brushes when you let off it shorts the brushes together. This then acts like a generator with nothing to power it. With the built up energy in the motor and the brushes being shorted is what causes the spark you can sometimes see when letting off the switch.

The brushes would have to be good and " part" of the switch good for it to run.

 

[Soundguy]

i figured it was doing some electic breaking either on field or brushes when off.

 

[Zebrafive]

I have a Delta 34-080 saw. It has a D handle. On the inside of the D handle is the motor switch. On the outside of the D handle is a red button labeled BRAKE. Mine works, but never new the mechanics of it.

 

[Soundguy]

i've seen others like that with a seperate switch.

 

[John_in_TN]

Steave's description is correct. When the Switch is released it should direct power coming out of the generator (the coasting motor) back to the brushes in a reverse direction.
The problem could certainly be the Switch but a dirty "commutator" can also cause this problem. I reccomend you try cleaning the Brushes & Commutator with an appropriate cleaner stick.
Good Luck!

 

[Soundguy]

f the comutator were dirty, would it not run well, since it's using the same brushes in the same contact area?

in usingthe brushes and reverse em.. is it crossing the brushes at off.

 

[kevinwak]

Worn/dirty brushes can cause the electric rake to fail. Had a Makita miter saw that the brake wouldn't work when the brushes wore, even though the saw still ran great.

Sent from my iPhone using TractorByNet