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Eddy Current Lathe Brake?

abstruse

Plastic
Joined
Jul 24, 2020
Anyone ever play with making an eddy current brake for a full size (13"x40") lathe> ECBs won't fully stop a thing, but they'll slow it down a lot, then friction takes over.

I've worked with electromagnetic ECBs for another project. Permanent magnets work also.
 
Anyone ever play with making an eddy current brake for a full size (13"x40") lathe> ECBs won't fully stop a thing, but they'll slow it down a lot, then friction takes over.

I've worked with electromagnetic ECBs for another project. Permanent magnets work also.

I run a 13x40 lathe most of the time, and unless I had something really massive in the lathe, I'm unsure why I'd need more braking ability than the foot spindle brake gives me. A 13x40 lathe isn't what I'd call a "full size" lathe... it's fairly modest in size.
 
A eddy current brake works good at high speed and goes to zero at low speed, think of it as a shorted generator...Phil

Right - I'm familiar with what they are and how they work, just not with the need for one on a 13x40 lathe.

One thing I'd ponder on a machine tool is if it is being driven by a 3-phase induction motor, whether DC injection braking could be accomplished.
 
We had the safety department rush round, they wanted DC injection brakes on just about anything, tried to tell them it’s not such a good idea with a screwed on Chuck ( old machines over here often do have those), they insist you do, First test, triggered the whatsimadohdah, spindle stops, no one told the Chuck to stop, screwed right off and hit the bed, they weren’t happy, we must have fitted it wrong!, solution, replace the lathe, it’s in my shop now, (Harrison 12”) same happened on a few more, they even wanted one on an 80” craven monster,
Mark
 
There was one added onto a 16" radial arm saw at one high school. It made a god awful high frequency shriek that was painful to listen to. Like fingernails on a blackboard. Not super loud but very annoying.
Bil lD
 
Bill D., that's surprising, since there's no mechanical contact in these brakes. Still, I can imagine that some noise could come from some source.

The modest, quick-and-dirty test I recently did made no noise that I could hear. I am, however, almost deaf when it comes to high freqency sounds.

Dalmatiangirl61, not really much practical benefit. I do have a foot brake. But it seems that it'd be nice for the chuck to stop quickly every time, without my having to wear down the brake linings.
 
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