A co-worker asked my opinion of the current worksite table saws out there. He
mentioned that he had seen the Bosch 4000 at Cosco along with the Dewalt 744.
He said he was leaning towards the Bosch 4000 because it had a 4HP motor.
"What? No, way!" I told him, then he proceeded to show me Bosch's web site
where in fact they claim:

* Powerful 15 Amp, 4.4 HP max. tool output - Power to tackle any material

OK, how are they claiming to get 4.4 HP out of this thing on 115v?


Wayne

"Wayne Brissette" wrote in message
thlink.net...
A co-worker asked my opinion of the current worksite table saws out there.
He
mentioned that he had seen the Bosch 4000 at Cosco along with the Dewalt
744.
He said he was leaning towards the Bosch 4000 because it had a 4HP motor.
"What? No, way!" I told him, then he proceeded to show me Bosch's web site
where in fact they claim:

* Powerful 15 Amp, 4.4 HP max. tool output - Power to tackle any material

OK, how are they claiming to get 4.4 HP out of this thing on 115v?

It is based on stall speed output, not real HP. It is an advertising
gimmick. Check the watts for true comparison. 1 HP = 746 watts.
Ed

http://pages.cthome.net/edhome

Ed Pawlowski responds:

* Powerful 15 Amp, 4.4 HP max. tool output - Power to tackle any material

OK, how are they claiming to get 4.4 HP out of this thing on 115v?

It is based on stall speed output, not real HP. It is an advertising
gimmick. Check the watts for true comparison. 1 HP = 746 watts.

One hore does equal 746 watts, but--that would mean the Bosch delivers 2-1/3
horses, which I am sure is high. You probably need to figure 65% of that, for
motor efficiency, though it might be as high as 70%. So, at 70%, you have 1.63
HP. Which is very close to 1-1/2 HP.

Charlie Self
"Take care of the luxuries and the necessities will take care of themselves."
Dorothy Parker

http://hometown.aol.com/charliediy/m.../business.html

Mr. Self confirmed...

One hore does equal 746 watts, but--that would mean the Bosch delivers 2-1/3
horses, which I am sure is high. You probably need to figure 65% of that, for
motor efficiency, though it might be as high as 70%. So, at 70%, you have 1.63
HP. Which is very close to 1-1/2 HP.



My Grizz DC is only rated at 2HP, sucking up 12 amps of 230 volt
power. Let's see, crunching the numbers, the motor is capable of
3.7HP, so it's only 54% efficient. Is that a mark of poor quality, or
just an overly honest appraisal of the motor's output?

Joe

Big Joe asks:


My Grizz DC is only rated at 2HP, sucking up 12 amps of 230 volt
power. Let's see, crunching the numbers, the motor is capable of
3.7HP, so it's only 54% efficient. Is that a mark of poor quality, or
just an overly honest appraisal of the motor's output?

It's probably just an honest rating. I don't really know the various efficiency
ratings for different types of motors, and I'm too lazy to look them up right
now, but I would GUESS (let's emphasize the guess again) that 60% is pretty
close to the norm.

Charlie Self
"Take care of the luxuries and the necessities will take care of themselves."
Dorothy Parker

http://hometown.aol.com/charliediy/m.../business.html

Hello there,

The motor is 1.5 HP.

The only time it is 4 hp is during a blue moon with all the planets in
alignment, with the rotor locked, for one brief millisecond, just before it
blows up.

Thanks,

David.

Every neighbourhood has one, in mine, I'm him.

Remove the "splinter" from my email address to email me.

Newbies, please read this newsgroups FAQ.

rec.ww FAQ http://www.robson.org/woodfaq/
Archives http://groups.google.com/advanced_group_search
Crowbar FAQ http://www.klownhammer.org/crowbar

On Mon, 19 Jan 2004 11:39:28 GMT, Wayne Brissette
wrote:

A co-worker asked my opinion of the current worksite table saws out there. He
mentioned that he had seen the Bosch 4000 at Cosco along with the Dewalt 744.
He said he was leaning towards the Bosch 4000 because it had a 4HP motor.
"What? No, way!" I told him, then he proceeded to show me Bosch's web site
where in fact they claim:

* Powerful 15 Amp, 4.4 HP max. tool output - Power to tackle any material

OK, how are they claiming to get 4.4 HP out of this thing on 115v?


Wayne


That quite a bit, like running three toasters at the same time. I'd
much rather have a quality fence and 1 HP, than a so-so fence and 4.4
HP.

Ah, Craftsman is also that type of tool. A $200 saw that develops 3,4
maybe more hp. All on a 110 circuit.


On Mon, 19 Jan 2004 13:26:45 GMT, Phisherman wrote:


On Mon, 19 Jan 2004 11:39:28 GMT, Wayne Brissette
wrote:

A co-worker asked my opinion of the current worksite table saws out there. He
mentioned that he had seen the Bosch 4000 at Cosco along with the Dewalt 744.
He said he was leaning towards the Bosch 4000 because it had a 4HP motor.
"What? No, way!" I told him, then he proceeded to show me Bosch's web site
where in fact they claim:

* Powerful 15 Amp, 4.4 HP max. tool output - Power to tackle any material

OK, how are they claiming to get 4.4 HP out of this thing on 115v?


Wayne


That quite a bit, like running three toasters at the same time. I'd
much rather have a quality fence and 1 HP, than a so-so fence and 4.4
HP.

In rec.woodworking
Phisherman wrote:

That quite a bit, like running three toasters at the same time. I'd
much rather have a quality fence and 1 HP, than a so-so fence and 4.4
HP.

Really? I've got to let your rip some of this 8/4 white oak I have and see
how fast you change your mind. Having ripped it on my 1.5HP with a Forrest
WWII and on my buddies 3HP Jet with a Forrest WWII, I can tell you that HP
is wonderful.

Bruce responds:


Really? I've got to let your rip some of this 8/4 white oak I have and see
how fast you change your mind. Having ripped it on my 1.5HP with a Forrest
WWII and on my buddies 3HP Jet with a Forrest WWII, I can tell you that HP
is wonderful.


Yeah, but that 3 HP Jet is on a 220 circuit. The Bosch is a 110 machine. It
does not turn out a realistic 4.4 HP. More like 1.5 which is actually
sufficient for most hobby woodworking, though 8/4 oak is going to be a slow
feed item.

Charlie Self
"Take care of the luxuries and the necessities will take care of themselves."
Dorothy Parker

http://hometown.aol.com/charliediy/m.../business.html

In rec.woodworking
otforme (Charlie Self) wrote:

Bruce responds:


Really? I've got to let your rip some of this 8/4 white oak I have and see
how fast you change your mind. Having ripped it on my 1.5HP with a Forrest
WWII and on my buddies 3HP Jet with a Forrest WWII, I can tell you that HP
is wonderful.


Yeah, but that 3 HP Jet is on a 220 circuit. The Bosch is a 110 machine. It
does not turn out a realistic 4.4 HP. More like 1.5 which is actually
sufficient for most hobby woodworking, though 8/4 oak is going to be a slow
feed item.

Yes, the Jet is on 220. The problem with slow feed is that it burns the
wood. I basically can't cut the oak without burning it so I have to
overcut and joint it.

Wayne Brissette writes:
* Powerful 15 Amp, 4.4 HP max. tool output - Power to tackle any material

15 amps maxes out at 2.4 HP. Unless they've invented something that
changes the laws of physics, they're misleading you.

On Mon, 19 Jan 2004 11:39:28 GMT, Wayne Brissette
wrote:

A co-worker asked my opinion of the current worksite table saws out there. He
mentioned that he had seen the Bosch 4000 at Cosco along with the Dewalt 744.
He said he was leaning towards the Bosch 4000 because it had a 4HP motor.
"What? No, way!" I told him, then he proceeded to show me Bosch's web site
where in fact they claim:

* Powerful 15 Amp, 4.4 HP max. tool output - Power to tackle any material

OK, how are they claiming to get 4.4 HP out of this thing on 115v?


Wayne


by lying....

On Mon, 19 Jan 2004 10:04:31 -0700, Bridger wrote:

On Mon, 19 Jan 2004 11:39:28 GMT, Wayne Brissette
wrote:

A co-worker asked my opinion of the current worksite table saws out there. He


* Powerful 15 Amp, 4.4 HP max. tool output - Power to tackle any material

OK, how are they claiming to get 4.4 HP out of this thing on 115v?


Wayne


by lying....
Maybe.

If I'm doing this right:
4.4HP = 3.28Kw at 100% eff. (which it isn't, of course)
3.28Kw of power at 120v requires 27 amps.

Creative. I have seen other products with similar claims
though.

Joe
Ontario

Joe notes:


On Mon, 19 Jan 2004 11:39:28 GMT, Wayne Brissette
wrote:

A co-worker asked my opinion of the current worksite table saws out there.
He


* Powerful 15 Amp, 4.4 HP max. tool output - Power to tackle any material

OK, how are they claiming to get 4.4 HP out of this thing on 115v?


Wayne


by lying....
Maybe.

If I'm doing this right:
4.4HP = 3.28Kw at 100% eff. (which it isn't, of course)
3.28Kw of power at 120v requires 27 amps.

Creative. I have seen other products with similar claims

Almost all shop vacuum cleaners...I've got one that's 5 HP, another that's
6-1/2 and a 4 HP small unit, all for 110 volts. Routers. How many 110 volt 3 to
3-1/2 HP routers are there on the market?

Charlie Self
"Take care of the luxuries and the necessities will take care of themselves."
Dorothy Parker

http://hometown.aol.com/charliediy/m.../business.html

In article ,
Joe wrote:

If I'm doing this right:
4.4HP = 3.28Kw at 100% eff. (which it isn't, of course)
3.28Kw of power at 120v requires 27 amps.

Well, on a 15A circuit, you get 15A in one wire and 15A out the other,
so it adds up to 30A. Isn't that how it works? :-)

On Mon, 19 Jan 2004 14:19:09 -0500, Roy Smith wrote:

In article ,
Joe wrote:

If I'm doing this right:
4.4HP = 3.28Kw at 100% eff. (which it isn't, of course)
3.28Kw of power at 120v requires 27 amps.

Well, on a 15A circuit, you get 15A in one wire and 15A out the other,
so it adds up to 30A. Isn't that how it works? :-)

That's like looking at a water pipe. Looking to the left, here comes 15
gallons per minute. Looking to the right, there goes 15 gallons per
minute. Must be 30 gallons per minute flowing in that pipe ;-)

-Doug

Roy Smith writes:
Joe wrote:

If I'm doing this right:
4.4HP = 3.28Kw at 100% eff. (which it isn't, of course)
3.28Kw of power at 120v requires 27 amps.

Well, on a 15A circuit, you get 15A in one wire and 15A out the other,
so it adds up to 30A. Isn't that how it works? :-)

No. They're going in opposite directions so they cancel.
You get zero amps from your 15A circuit which makes the
4.4 HP even more miraculous.

Less than truth in advertising...

That MAX hp output is weasel words, the saw is NOT a true 4+hp motor

John

On Mon, 19 Jan 2004 11:39:28 GMT, Wayne Brissette
wrote:

A co-worker asked my opinion of the current worksite table saws out there. He
mentioned that he had seen the Bosch 4000 at Cosco along with the Dewalt 744.
He said he was leaning towards the Bosch 4000 because it had a 4HP motor.
"What? No, way!" I told him, then he proceeded to show me Bosch's web site
where in fact they claim:

* Powerful 15 Amp, 4.4 HP max. tool output - Power to tackle any material

OK, how are they claiming to get 4.4 HP out of this thing on 115v?


Wayne

I think that it has two cords.

-Jack


"Wayne Brissette" wrote in message
thlink.net...
A co-worker asked my opinion of the current worksite table saws out there.
He
mentioned that he had seen the Bosch 4000 at Cosco along with the Dewalt
744.
He said he was leaning towards the Bosch 4000 because it had a 4HP motor.
"What? No, way!" I told him, then he proceeded to show me Bosch's web site
where in fact they claim:

* Powerful 15 Amp, 4.4 HP max. tool output - Power to tackle any material

OK, how are they claiming to get 4.4 HP out of this thing on 115v?


Wayne

15 amps @ 120 volts = 2.41 horsepoer. They lie.
"Wayne Brissette" wrote in message
thlink.net...
A co-worker asked my opinion of the current worksite table saws out there.
He
mentioned that he had seen the Bosch 4000 at Cosco along with the Dewalt
744.
He said he was leaning towards the Bosch 4000 because it had a 4HP motor.
"What? No, way!" I told him, then he proceeded to show me Bosch's web site
where in fact they claim:

* Powerful 15 Amp, 4.4 HP max. tool output - Power to tackle any material

OK, how are they claiming to get 4.4 HP out of this thing on 115v?


Wayne

Figuring in efficiency and power factor, the best it's gonna be is ~1.5hp.

--
Al Reid

"It ain't what you don't know that gets you into trouble. It's what you know
for sure that just ain't so." --- Mark Twain

"CW" wrote in message ...
15 amps @ 120 volts = 2.41 horsepoer. They lie.
"Wayne Brissette" wrote in message
thlink.net...
A co-worker asked my opinion of the current worksite table saws out there.
He
mentioned that he had seen the Bosch 4000 at Cosco along with the Dewalt
744.
He said he was leaning towards the Bosch 4000 because it had a 4HP motor.
"What? No, way!" I told him, then he proceeded to show me Bosch's web site
where in fact they claim:

* Powerful 15 Amp, 4.4 HP max. tool output - Power to tackle any material

OK, how are they claiming to get 4.4 HP out of this thing on 115v?


Wayne

No, the best it is ever going to be is 2.41 horsepower. Small motors are
rated in INPUT power.

"Al Reid" wrote in message
...
Figuring in efficiency and power factor, the best it's gonna be is ~1.5hp.

--

CW wrote:

No, the best it is ever going to be is 2.41 horsepower. Small motors
are rated in INPUT power.

Ha! So _this_ is how Bosch routers went from 2HP to 2.25HP without a
change in the motor!

--
gabriel

"CW" wrote in message ...
No, the best it is ever going to be is 2.41 horsepower. Small motors are
rated in INPUT power.

Not according to the NEC and NEMA.

"Al Reid" wrote in message
...
Figuring in efficiency and power factor, the best it's gonna be is ~1.5hp.

--

The best the two organizations do is say that "this is what we would like
you to do". If anybody followed that, we wouldn't have 6 HP shop vacs.
That's why our customers used to bring us their motors for rebuld. They
could either rebuild the old 2000 HP motor or they would have to buy a
modern 3500 to replace it.
"Al Reid" wrote in message
...

"CW" wrote in message
...
No, the best it is ever going to be is 2.41 horsepower. Small motors are
rated in INPUT power.

Not according to the NEC and NEMA.

"Al Reid" wrote in message
...
Figuring in efficiency and power factor, the best it's gonna be is
~1.5hp.

--

"Wayne Brissette" wrote in message
OK, how are they claiming to get 4.4 HP out of this thing on 115v?



By useing the same math that Porter Cable uses on my 7 HP air compressor,
that draws 15 amps at 240 volts!
Greg

This is hilarious.

4.4HP * 746W = 3282.4W

3282.4W / 15A = 218.83V

If your 110/115/120V (however you want to rate it) circuit EVER reaches
that, you're going to melt stuff in your house.
Vpeak for 110Vrms is only about 155V. I've measured 125Vrms in the wall
before, which is a peak of 177V.

In short, it is IMPOSSIBLE for that saw to ever develop 4.4HP, presuming its
stall current is 15A, and it is running on a household 110V circuit (and
further presuming that the motor is operating at 100% efficiency, which it
is, of course, NOT).

Now, if it can draw 21A at Vpeak (155V) without turning in to a puddle, then
it can consume power equivalent to 4.4HP, though it still wouldn't be
cutting wood at that rating.







"Wayne Brissette" wrote in message
thlink.net...
A co-worker asked my opinion of the current worksite table saws out there.
He
mentioned that he had seen the Bosch 4000 at Cosco along with the Dewalt
744.
He said he was leaning towards the Bosch 4000 because it had a 4HP motor.
"What? No, way!" I told him, then he proceeded to show me Bosch's web site
where in fact they claim:

* Powerful 15 Amp, 4.4 HP max. tool output - Power to tackle any material

OK, how are they claiming to get 4.4 HP out of this thing on 115v?


Wayne

"effinperfectionist" wrote in message . com...
This is hilarious.

4.4HP * 746W = 3282.4W

3282.4W / 15A = 218.83V


You are playing the same game bu using "theoretical" numbers. You have to look at efficiency and power factor to knoe the actual
watts/hp

If your 110/115/120V (however you want to rate it) circuit EVER reaches
that, you're going to melt stuff in your house.
Vpeak for 110Vrms is only about 155V. I've measured 125Vrms in the wall
before, which is a peak of 177V.


peak-to-opeak voltave has nothing to do with it.

In short, it is IMPOSSIBLE for that saw to ever develop 4.4HP, presuming its
stall current is 15A, and it is running on a household 110V circuit (and
further presuming that the motor is operating at 100% efficiency, which it
is, of course, NOT).


the 15A is full load current (FLA) not locked rotor current.

Now, if it can draw 21A at Vpeak (155V) without turning in to a puddle, then
it can consume power equivalent to 4.4HP, though it still wouldn't be
cutting wood at that rating.



Still wrong since you are not taking efficiency and power factor in to account and you are using a ficticious voltage.

The long and short of it is that on a nominal 120vac circuit, a motor drawing 15 amps will produce `~1.5 hp. On a 20 Amp curcuir
you can eek out a little more at the expense of heat and speed. If the circuit is not limited, it will continue to slow down and
produce more power until it hist 'breakdown' and stalls. at that point it will deaw the Locked rotor current.

I am not sure why the manufacturers have taken to this silly rating game. I have a 1.5 hp Ingersol-Rand air compressor that is 1.5
HP and draws about 16 amps. The same compressor by today's 'standard' is rated at 6hp. That's great, except that in reality, they
do the same amount of work for the same power input.






"Wayne Brissette" wrote in message
thlink.net...
A co-worker asked my opinion of the current worksite table saws out there.
He
mentioned that he had seen the Bosch 4000 at Cosco along with the Dewalt
744.
He said he was leaning towards the Bosch 4000 because it had a 4HP motor.
"What? No, way!" I told him, then he proceeded to show me Bosch's web site
where in fact they claim:

* Powerful 15 Amp, 4.4 HP max. tool output - Power to tackle any material

OK, how are they claiming to get 4.4 HP out of this thing on 115v?


Wayne

Al Reid wrote:
"Still wrong since you are not taking efficiency and power factor in to
account and you are using a ficticious voltage."

No, I'm not wrong. I said IF it could actually DRAW 21A at the peak voltage
of 155V, then the math gives you power consupmtion of 4.4HP. Efficiency is
not relevant, as I'm talking purely about consumed power (input power).
Thus, if a 21A peak coincides with a 155V peak, the power consumption at
that moment is 4.4HP. I am NOT talking about power delivered to the cutting
teeth, or wherever else you may choose to measure it, I'm talking about the
total consumed power of the machine.

And, 155V is not ficticious.......it's the peak instantaneous voltage for a
110V sine wave.
(110VACrms / 0.707)

To quote myself:

" Now, if it can DRAW 21A at Vpeak (155V) without turning in to a puddle,
then
it can CONSUME POWER EQUIVALENT to 4.4HP, though it still wouldn't be
cutting wood at that rating."

"effinperfectionist" wrote in message
. com...
Al Reid wrote:
"Still wrong since you are not taking efficiency and power factor in to
account and you are using a ficticious voltage."

No, I'm not wrong. I said IF it could actually DRAW 21A at the peak
voltage
of 155V, then the math gives you power consupmtion of 4.4HP. Efficiency
is
not relevant, as I'm talking purely about consumed power (input power).
Thus, if a 21A peak coincides with a 155V peak, the power consumption at
that moment is 4.4HP. I am NOT talking about power delivered to the
cutting
teeth, or wherever else you may choose to measure it, I'm talking about
the
total consumed power of the machine.

And, 155V is not ficticious.......it's the peak instantaneous voltage for
a
110V sine wave.
(110VACrms / 0.707)


It is still meaningless. It is not a DC machine. It is still rated based on
the RMS input voltage. Mow if you wnnt to apply a higher (155VRMS) input
voltage, then you would be correct.

The only measure that has any value is the HP and torque at the output
shaft. I don't care how many amps go in, I want to know how much HP is
developed.

To quote myself:

" Now, if it can DRAW 21A at Vpeak (155V) without turning in to a puddle,
then
it can CONSUME POWER EQUIVALENT to 4.4HP, though it still wouldn't be
cutting wood at that rating."

On Wed, 21 Jan 2004 02:58:00 GMT, "Al Reid"
wrote:



The only measure that has any value is the HP and torque at the output
shaft. I don't care how many amps go in, I want to know how much HP is
developed.




I doubt you will ever see that information given for a power tool. I
suspect that that number would shock the american buying public, who
think that they own 6 HP vacuum cleaners and such. I doubt that output
HP on one of sears' 6 HP specials would exceed 1/4 HP or so....

A motor _should_ be rated by the HP it can deliver continuously.
Additional ratings are often given for various duty cycle such as a 1
hour rate (normally 10 to 20 % higher than continuous) at which the
motor can be loaded for 1 hour without overheating.
Most AC induction motors can develop two to four times their
continuous rating for a short time. This has nothing to do with stall
condifiton since with a stalled rotor, not power is being developed -
although a lot of power is going in and being turned to heat.

The current rating of a motor should be the current it draws at rated
voltage when developing rated continuous power.

As to efficiency - it depends on many things. It varies with the
motor constuction which can provide in excess of 90% maximum efficency
to less than 60% for a lousy motor at peak effciency. It also depends
on load. Peak efficiency normally occurs under light load and drops
as the motor is loaded to its continuous rating (whick can still be
over 80% efficiency) and continues down as the motor is loaded closer
to its peak rating.

If you will note, most of these inflated power ratings have the words
peak or maximum. This peak can be reached momentarily either by a
fused circuit for a brief time as the fuse becomes overloaded and then
reacts to the overload, or by a circuit (just for testing) that can
supply whatever current the motor asks for.

The best lies are 99% true. I'll bet these inflated ratings can be
backed up by actual data. What isn't said is that these test
conditions can't be approached in ordinary use.

Allen