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Drill speed brake - How does it work?

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moody07747

Member
Last year I was given a craftsman 19.2 volt drill and was impress by the speed brake.

I had heard all about them but never had a drill that had the feature.

after all that I started to wonder how the speed brake on a drill worked.

one thing I found is that if I removed the battery and turned the drill by hand with my finger off the triger, the drill would be hard to turn, but if I turned the drill by hand with the trigger pressed, it turns easyer.

now that just confused me because that means that the speed brake does not use the battery as I thought it might?


so...How does this speed brake system work :?:
 

Nigel Goodwin

Super Moderator
Most Helpful Member
I'm presuming you mean 'brake' and not 'break' - which are rather different things!.

Some of the drills I've seen are purely mechanical, the motor is prevented from turning completely when you release the trigger - this allows you to better use a keyless chuck.

But assuming it's electrical braking?, all you do is place a short circuit directly across the terminals of the motor - this makes the motor FAR more difficult to turn - try it on any small DC motor!.
 

jrz126

Active Member
It possibly could short the wires going to the motor when the trigger is released?
If you try to spin a motor with the wires connected (shorted) it is pretty hard to turn.
Thats what I'm thinking from the way you describe it.

EDIT: I knew I should have refreshed this page
 

Klaus

New Member
moody07747 said:
you guys are corrents

its a short between the motor terminals
i also tried this on a small DC motor and it does make it very hard to turn

thanks for that info.

Yes, agreed, but it only applies to PM (permanent magnet) motors. Most small DC motors these days are PM.

Klaus
 
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