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.
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
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
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.
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.
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? ;~)
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
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