[TheForge] Re: Air hammer score

Tue Apr 23 20:04:01 2002

        Mike I was referring to the power required to turn a hydraulic pump.

    It takes 2 Hp(elect) to deliver 2gals/min @1500 psi.     It would take 3
Hp(mechanic) to deliver 2 gals/min @ 1500 psi.   This is my understaning so
you need slightly more umph on the mechanical Hp's.

Ralph


----- Original Message -----
From: "Mike Spencer" <[email protected]>
To: <[email protected]>
Sent: Tuesday, April 23, 2002 2:26 PM
Subject: [TheForge] Re: Air hammer score


>
> Yow!  Advice by overnight express! :-)
>
> >From Ralph:
>
> > I have one suggestion is that you have to use a larger engine HP
> > than the electric one on it.
>
> Yeah.  I knew there was some kind of thing like that but don't know
> any of the engineering or even rules of thumb.  The ex works machine
> has a 15 HP, 60 Hz motor made in Canada for the Brit hammer.  The
> motor has a small gear on it that drives a big gear wheel on the
> hammer's integral compressor.  Pretty efficient drive.  The hammer I'm
> trading away is flat-belt and tensioner pulley (instead of a clutch) so
> I know from experience it's not a very efficient way to go.  The idea
> of using the 10HP make 'n break is just because I happen to have it.
> It's got lots of torque and runs at about the right speed so's not to
> need intermediate line-shafting.
>
> > If you have a 1HP elect.......I believe it is only 2/3 of a
> > mechanical HP in power supplied.
>
> Do you mean that an electric motor rated for 1HP only delivers 2/3 HP
> as measured by, say, a brake HP measuring thingy?  That should mean
> that 10HP delivered to the shaft would be adequate.  My (very vague)
> recollection is that electric motor HP is rated by the electric power
> delivered *to* the motor so that what's output by the motor, as
> measured by something like torque X RPM is less.  Could you go into
> more detail on that?
>
>
> Since I'm building a new shop at home, I'm going to pour the pad for
> the hammer outside at the same time.  It'll be easy enough to move the
> gas engine to a temporary mount and try it.  I talked to the manager
> of Acadia Gas back before they were borged by a more modern company
> and were still making these has engines.  He said they actually
> delivered 11+ HP.
>
> (Putting the hammer outside initially is just caution.  If I were to
> build the shop around it, I wouldn't have head room to lift the ram out
> if that proves necessary.  Worse, if I can't get it going at all, I'd
> almost have to tear the building down to get it out again.  If I can
> get it working outside, I'll just stick a shed on the side of the
> shop.  I'm framing a 10' piece of the wall ahead of time specially to
> make a 10' opening there easy later if needed.)
>
> And  Shannel said:
>
> > What about a rotary phase converter and a cheap, second hand 3 phase
> > motor, you can build your own phase converter for not a lot of
> > dough.
>
> Well, I guess that's a possibility.  The original motor and its very
> heavy mount bolt directly to the hammer base, a very (!) sturdy
> assembly, presumably because of the stresses on the ca. 6" -> 24" gear
> drive.  The motor shaft and castings are okay and I think I could get
> it rewound by a friend whose little backyard electric biz has grown up
> to be a major player in the local industrial park.  Sometime later
> this year I may be back, asking for pointers to how to do home-made
> converters.  I want to try the funky alternatives first and, if that
> doesn't work, I'll have to look through all the posts to TheForge that
> I've saved.  I know this 3ph converter stuff has gone by before.
>
>
> All very exciting but rather intimidating.
>
> - Mike
>
> ---
>
> Michael Spencer                  Nova Scotia, Canada
>
> http://home.tallships.ca/mspencer/
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