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Re: [PSUBS-MAILIST] Horsepower
I date myself. - Joe
----- Original Message -----
From: Greg Teiber <wolfe19@megsinet.net>
To: <personal_submersibles@psubs.org>
Sent: Thursday, January 27, 2000 8:03 PM
Subject: Re: [PSUBS-MAILIST] Horsepower
> Actually companys are now not puling that stunt. that was the norm in the
50-70's
>
> *********** REPLY SEPARATOR ***********
>
> On 1/27/00, at 7:38 PM, Marsee Skidmore wrote:
>
> >One other goofy detail about ratings. Internal combustion engines are
rated
> >on a dynamometer with almost none of the parasitic loads. None of those
> >pesky accessories like a water pump, fuel pump or radiator fan. - Joe
> >
> >----- Original Message -----
> >From: Greg Teiber <wolfe19@megsinet.net>
> >To: <personal_submersibles@psubs.org>
> >Sent: Thursday, January 27, 2000 12:53 AM
> >Subject: Re: [PSUBS-MAILIST] Horsepower
> >
> >
> >> electric motor's have maximum torque at 0rpm. GAs motors have maximum
> >torque somewhere pretty high, anywhere from 1000rpm in the Jag XJ motors,
to
> >7000rpm in the honda S2000 :) problem is, Horesepower IS Horsepower. a
> >60hp motor will do more work than a 20hp one. NO MATTER WHAT. That 20hp
is
> >driveable because it has such huge torque. Plain and simple. Drivers
like
> >torque. Then again, so do propellers. And what are we trying to turn :)
> >Electric motors are ideal for out situation.
> >>
> >> *********** REPLY SEPARATOR ***********
> >>
> >> On 1/27/00, at 12:26 AM, D. Blake wrote:
> >>
> >> >Yeah, and that peaky power-curve is why internal combustion engines
need
> >a
> >> >transmission and clutch. Both of which suck enormous amounts of
> >available
> >> >horsepower and energy through friction. The electric motor develops
> >torque
> >> >the instant you apply power, and maintains a more or less linear power
> >curve
> >> >throughout the RPM range. No need to rev the motor to obtain power,
and
> >no
> >> >need to waste energy by idling.
> >> >Pull your front tires up against the curb. See if that 60hp internal
> >> >combustion engine will push you over the top without a few revs of the
> >motor
> >> >and dumping the clutch. Do the same with a 20hp series-wound DC motor
> >with
> >> >direct-drive to the rearend, and you will go immediatly over the top.
> >> >The stuff I have read says it's not uncommon to go zero to sixty and
more
> >> >without ever having to shift gears. That is how linear the
power-curve
> >is
> >> >with electric motors.
> >> >Big Dave
> >> >-----Original Message-----
> >> >From: Marsee Skidmore <heyred@email.msn.com>
> >> >To: personal_submersibles@psubs.org <personal_submersibles@psubs.org>
> >> >Date: Wednesday, January 26, 2000 11:28 PM
> >> >Subject: Re: [PSUBS-MAILIST] Horsepower
> >> >
> >> >
> >> >>The difference is in how the ratings are done. Electric motors have a
> >> >fairly
> >> >>linear power curve (hp vs. rpm), and are derated for continuous duty.
In
> >> >>other words, the rated horsepower of an electric motor is on the low
end
> >of
> >> >>the output curve, just to be conservative. Internal combustion
engines
> >have
> >> >>a very peaky power curve, and are rated by the peak output.
> >Conservative,
> >> >>conshmervative, let's sell cars! Race car drivers like to run at the
> >peak
> >> >of
> >> >>the power curve, but those of us who pay for their own gas and
overhauls
> >> >>operate a little bit further down on the curve. Three to one sounds
> >about
> >> >>right. A 60 hp Volkswagen runs just fine with a 20 hp electric
motor. -
> >Joe
> >> >>----- Original Message -----
> >> >>From: <SeaLordOne@aol.com>
> >> >>To: <personal_submersibles@psubs.org>
> >> >>Sent: Wednesday, January 26, 2000 5:59 PM
> >> >>Subject: [PSUBS-MAILIST] Horsepower
> >> >>
> >> >>
> >> >>> Teammates,
> >> >>>
> >> >>> Please help me with this one. According to an article in BOAT/U.S.
> >> >>Magazine
> >> >>> (January 2000, pages 24-25), electric motors somehow provide three
> >times
> >> >>the
> >> >>> performance of internal combustion engines. How can this be?
> >Horsepower
> >> >>is
> >> >>> horsepower is horsepower, isn't it?
> >> >>>
> >> >>> The article (Electric Boats Charging Back) is about coverting
gasoline
> >or
> >> >>> diesel boats into electric ones. The author (Ryck Lydecker) says:
"He
> >> >>> calculates that to replace internal combustion engines,
particularly
> >in
> >> >>> sailboats, the power ratio is about three-to-one. That is, a 3-hp
> >> >>electric
> >> >>> motor is adequate to replace a 9-hp outboard." I thought a 3-hp
> >diesel =
> >> >>a
> >> >>> 3-hp gasoline = a 3-hp electric = a 3-hp anything. Yes? No?
Please
> >> >help
> >> >>me
> >> >>> out here. Does this guy know something I don't?
> >> >>>
> >> >>> Thanks,
> >> >>>
> >> >>> Doug
> >> >>>
> >> >>
> >> >>
> >> >>
> >>
>