# 4 HP on 115v??

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
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http://pages.cthome.net/edhome
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Ed Pawlowski responds:

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
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Mr. Self confirmed...

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

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

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In rec.woodworking

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.
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Bruce responds:

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
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In rec.woodworking snipped-for-privacy@aol.comnotforme (Charlie Self) wrote:

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.
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15 amps maxes out at 2.4 HP. Unless they've invented something that changes the laws of physics, they're misleading you.
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On Mon, 19 Jan 2004 11:39:28 GMT, Wayne Brissette

by lying....
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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
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Joe notes:

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

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
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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.
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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

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I think that it has two cords.
-Jack

He
744.
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