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Posted by You on April 17, 2007, 2:16 pm
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> Neon John wrote:
>
> >
> >>I've got a 11hp 5kw McCulloch pull start generator, was wondering if it
> >>could be converted somehow to use the gen as a starter motor to start the
> >>engine, then run as a generator?
> >>Thanks,
> >>Eric
> >
> > Possible? Yes. Practical? Probably not.
> >
> > Here's what is involved.
> >
> > First, the field must be excited much more strongly than for normal
> > operation. This aids in producing enough torque to turn over the cold
> > engine. If yours is a brushless design then slip rings and brushes
> > must be fitted.
> >
> > Provisions would have to be made to reconfigure the stator to 2 and
> > ideally, 3 phase configuration. This would involve a number of power
> > contactors.
> >
> > A custom solid state variable speed drive would have to be designed to
> > draw power from the available source (12vdc? 24vdc maybe) and invert
> > it to the type of drive the stator would require. What we've created
> > is essentially a crude stepper motor with a wound rotor.
> >
> > Because this lashup still won't generate much torque, you'll probably
> > have to arrange a valve lifter compression release.
> >
> > I had an Onan AJ one time that used the generator to crank the engine
> > but it had a separate high current DC series field and a separate
> > commutator on the rotor just for starting. Normal output was from a
> > pair of adjacent slip rings. It had an oil pressure-operated valve
> > lifter that let the engine spin up a little before cranking commenced.
> >
> > Assuming that this generator of yours is a modern one where McCullough
> > is just a name stuck on the side, then it probably has a Briggs
> > engine. Converting that to electric start involves little more than
> > buying the kit and attaching it. You might have to drill and tap the
> > mounting bosses for the starter motor and you might have to buy a
> > flywheel equipped with a ring gear.
> >
> > Or just sell the thing and buy one already equipped with electric
> > start. Given how cheap the lower end generators have become, you'd be
> > dollars ahead even if you didn't get much for your old one.
> >
> > John
> > ---
> > John De Armond
> > See my website for my current email address
> > http://www.neon-john.com
> > Cleveland, Occupied TN
> > All great things are simple and many can be expressed in single words:
> > Freedom, Justice, Honor, Duty, Mercy, Hope. -Churchill
>
> ok, ok - I'll pull the rope! :-)
> Eric
> ps: but what if i...
A very Excellent Resource for Gensets and Engines is www.smokstak.com
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