Whirlwind or Sawstop

Lodgepole · Post by **Lodgepole** » Tue Apr 03, 2012 7:33 pm

Has anyone else seen this video?

Any thoughts?

http://www.whirlwindtool.com/index.php? ... &Itemid=50

terrydowning · Post by **terrydowning** » Tue Apr 03, 2012 7:59 pm

Wonder if the whirlwind will work with SS? It should since it is working with other AC induction motors.

I like the concepts of an after market retrofit. If you want it, you got it. If you don't, you don't.

moose · Post by **moose** » Tue Apr 03, 2012 8:02 pm

This has been discussed elsewhere on the forum, however, this is a no brainer. Does not destroy the blade, does not destroy the module. Absolutely just as effective and you don't have to physically touch the blade to accuate the mechanism. If we are forced into something like this, I would hope it would be this or something similar. FWIW, several power tool companies have already endorsed this system.

algale · Post by **algale** » Tue Apr 03, 2012 10:27 pm

ashbury wrote: FWIW, several power tool companies have already endorsed this system.

Where do you get that idea? Everything I read says he's he is still looking for a deal with a company and no endorsements. The reference to power tool companies is just him showing his system can be used on those saws. He is also careful to say that these names are the trademarks of their respective owners.

damagi · Post by **damagi** » Tue Apr 03, 2012 10:49 pm

ashbury wrote:This has been discussed elsewhere on the forum, however, this is a no brainer. Does not destroy the blade, does not destroy the module. Absolutely just as effective and you don't have to physically touch the blade to accuate the mechanism. If we are forced into something like this, I would hope it would be this or something similar. FWIW, several power tool companies have already endorsed this system.

Its definitely interesting to take a step back and consider what each system protects against, and the potential damage associated with the emergency stop (both to the operator, and to the saw).

One of the things that I like about the whirlwind design is that they assume that you should stop the problem before it becomes dangerous rather than reacting once the problem has arrived. Its the difference between antilock breaks vs. airbags. Certainly both save lives, but I think we are all happy that we have used ABS much more often than airbags. Its interesting the suggestion of using the emergency stop functionality as a teaching tool. It would be interesting if cars let the operator know when ABS ended up being required.

Another interesting thing is that both the SawStop and the whirlwind setup take into account dust collection as a major potential source of harm as well.

Given the current video, I think they are heading in the right direction. The one thing neither system shows the more catestrophic scenario. Sure, the hotdog test is a good one to demonstrate the careless blade contact. Certainly, by using riving knives and such the risk of kickback is also reduced. I guess I would love to know how many table saw injuries these systems cover (90%, 50%, 10% ?).

The whirlwind system would be a great fit for the shopsmith it seems. One great advantage with the powerpro is that you should be able to stop the blade very quickly and safely. Its also ideally suited since you could share the detection unit with all the SPTs in a very natural fashion.

billmayo · Post by **billmayo** » Wed Apr 04, 2012 5:40 pm

Quite impressive. The extended blade guards alone would greatly help keep fingers away from the blade. I am impressed with the ability to instantly stop the motor.

I spend a few months years ago playing with various ways to immediately stop the motor and anything it was turning as an immediate shutoff for bowl and lathe turning problems. Even after destroying several motors, I was never able to determine how to electrical lock or stop the rotor without other problems and damage. I build several control boxes with various transformers and relays with different connections to produce counter EMF and/or attempt to instantly reverse the motor, all without success. I would love to see the concept and/or internal schmetic for his control box.

terrydowning · Post by **terrydowning** » Wed Apr 04, 2012 6:58 pm

I bet there's a bunch of other people that would too!

JPG · Post by **JPG** » Thu Apr 05, 2012 12:12 am

terrydowning wrote:I bet there's a bunch of other people that would too!

I think the 'secret'(he alluded to it) is the timing of the application of the DC at the instant the run current is at a maximum thus maximizing 'braking'. Polarity would be relevant as well.

billmayo · Post by **billmayo** » Fri Apr 06, 2012 12:37 am

JPG40504 wrote:I think the 'secret'(he alluded to it) is the timing of the application of the DC at the instant the run current is at a maximum thus maximizing 'braking'. Polarity would be relevant as well.

It is not that simple to stop the rotor. I tried all the above ideas without success. Of course I did not have a computer for any kind of switching. AC motor do not tolurate DC currents with out problems. A mechanican brake proved to be expensive and had many problems but had delay in stoping the rotor. Does any have a price yet. I might buy one just to see how they did it and see if I can duplicate it on other motor driven machines as an emergency stop which most machines do not have.

JPG · Post by **JPG** » Fri Apr 06, 2012 1:52 am

billmayo wrote:It is not that simple to stop the rotor. I tried all the above ideas without success. Of course I did not have a computer for any kind of switching. AC motor do not tolurate DC currents with out problems. A mechanican brake proved to be expensive and had many problems but had delay in stoping the rotor. Does any have a price yet. I might buy one just to see how they did it and see if I can duplicate it on other motor driven machines as an emergency stop which most machines do not have.

I did not say for very long! He may be using a capacitor discharge to limit the duration.

Indeed too much DC for too long leads to space heater!:D