Answer from SawStop

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On 12/7/2012 12:32 PM, dpb wrote:

Ok he said it might work for 1~2 seconds. BUT because it takes longer for spin down to happen it is not going to protect during the whole spin down time period, only the first 1~2 seconds.
Since you do not know what my question to him was, that may be the problem. I asked if the saw would protect in the even of a power failure. A simple answer of NO would have been sufficient if it would not protect during a power failure. Because as he explained, the cartridge might stay powered for about 1-2 seconds at most while its internal voltage falls off, you might be protected for the second or two after the power failure.
After that period of time you would not be protected during the remainder of the coast down.
Either way, you are likely to be cut if every thing goes wrong but there is a slight window of opportunity where you ge an extra second or two that another brand saw would not afford you.
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wrote:

In reality, how much protection do you need? Spin down of a blade with no load takes a few seconds, a blade in the middle of a cut stops quickly by comparison. I've had the lights go out. I just froze until everything was quiet. Normal reaction time would still keep you a good distance from the blade if you were still pushing.
Yes, things can go wrong and we can argue theory all day, but in real life, I don't see it as a problem. Certainly not a deal beaker for me.
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On 12/8/2012 10:45 AM, Ed Pawlowski wrote:

Exactly
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On 12/8/2012 8:36 AM, Leon wrote: ...

...
OK, I said I wouldn't but... :)
I spent a number of years designing, analyzing and licensing safety systems for commercial reactors (amongst many other things alongst the way; this was mostly early 10-15 yr).
If I had _ever_ written such an assessment of a functional safety system or tried to weasel-word such testimony as a "might" to the ACRS (Advisory Committee on Reactor Safeguards the ultimate technical body that made the judgments on vendor issues before the NRC) it would certainly have been deemed as "doesn't work" and we'd have had to start over.
Not to mention, of course, my employer would have likely terminated me before the hearing was over for such incompetence as to think somehow that would be 'ok' for a safety system to perhaps work some of the time or then again, maybe it won't. :)
IOW, from what (I presume Dr Gass) wrote, it's clear the scenario is _not_ considered in the design and therefore it's almost purely happenstance if it were to happen to actually trigger under those circumstances. That, to me, is about as clear a "no" as it gets.
I think there's essentially no additional protection over any other saw under those conditions. That's not to say it isn't a well-designed and functional system for what the design _does_ include but there's no point in trying to claim it's capable of something that isn't intended on the basis of a random event occurring.
--
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On 12/8/2012 3:00 PM, dpb wrote:

Now I think we are seeing it the same way. ;~) The explanation would be similar to the selling the smoothness of the blade elevation wheel. You can turn it by hand or give it a quick spin and it will spin a few times on it's own. Not really a feature but something that might happen if the stars align properly.
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On 12/9/2012 7:58 AM, Leon wrote: ...

Glad to see you finally come around, Leon!!! :) <vbg,d&r)
--
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On 12/9/2012 8:42 AM, dpb wrote:

;~O
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@swbelldotnet says...

Why not write back to them/him, quote the explanation and say, "Is this a yes or a no?" and end all speculation.
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On 12/9/2012 7:21 AM, phorbin wrote:

Because the answer would be yes if every thing and the timing is just right for 1~2 seconds and no it would not work normally. It is not a designed feature so it might or might not work.
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And for you, why not trim over 120 lines of wasted text? "Is this a yes or a no?" and end the speculation that you know what you're doing.
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snipped-for-privacy@teksavvy.com says...

Fair enough... ...but you should probably make your own oatmeal.
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On 12/6/2012 6:28 PM, dpb wrote:

There is a chance that the moment b4 power loss, that this might think this is grounded and fire w/remaining voltage. But doubtful.
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Hmmmm..... a product flaw that is ripe for lawsuit picking. In the scenario where the power fails the workman cannot see to control the wood or keep his/her hands clear of the blade and gets badly cut as the saw is winding down. This problem was foreseeable and preventable... One or more large capacitors, or a UPS (uninterruptable power supply) on the safety device could have kept the safety device active for several seconds or more giving the saw time to wind down and the user to safely remove their hands from the danger area. Out lawyer the lawyer? ;~)
John
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On 12/6/2012 5:38 PM, John Grossbohlin wrote:

So do you propose going after the power company? Under normal circumstances the saw safety will work. If the lights go out and the motor looses power I suspect no one will blame the saw should an accident happen.
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No... poking fun at the flawless product...
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On 12/7/2012 11:17 AM, John Grossbohlin wrote:

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Leon wrote:

the coasting blade as they grab the cut-off piece of wood. Does the safety system remain active for more than two seconds after the saw is turned off?
--
G.W. Ross

Take my advice, I don't use it anyway.
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On 12/6/2012 6:06 PM, G. Ross wrote: ...

This isn't turning the saw off; it's loss of power _to_ the saw...totally different.
--



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On 12/6/2012 6:06 PM, G. Ross wrote:

Yes the system is active after the motor is turned off and the blade is still spinning.
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