direct drive methods?

[wildman]

i have read somewhere in these pages that a "hard" direct drive should be avoided. that you need the "cushion effect" of the spider in the lovejoy connector?? i have also read about using using something like a piece of tire or similiar material to make the connection. i believe i recall seeing something like this on an old washing machine transmission?

what is wrong with using a drive shaft with u-joints to drive a generator??

all info is appreciated- chuck

[rmchambers]

You can hide many a sloppy mounting using a flexible drive coupling.  If your engine shaft and your gen head shaft were perfectly aligned (height, left/right, and tilt) AND you are assured that neither of them could move independently of the other one then a fixed transmission would be the best and lowest loss method of transmitting power to the head.

In real life though things flex, things creep, things vibrate and all those movements would put undue stress on the shafts and bearings of both devices.  Having a flexible coupling like a Lovejoy lets you live with the small movements without causing the stress on the shafts and bearings.  There is some loss in a flexible coupler but it's usually not a whole lot and it's a lot easier to replace the urethane/rubber type cushions in a flex coupler every so often than it is to repair or replace the items doing the work.

An automotive driveshaft should work as it has flexible couplings on each end (assuming you use both) and the load you transmit down it probably won't be as severe as what it is used to as a car driveshaft.  There might be quite a bit of spinning mass in the steel shaft though which if you've ever been in a car/truck with a dodgy driveshaft will know it can set up some ugly vibrations.

Perhaps the half shaft of a front wheel drive vehicle could be employed to do it - something with the sealed CV joints they'd be small enough and short enough that you wouldn't need 5 feet between engine and gen head.  The nice thing about these things is that they are fairly common, you could pick a few up at a junk yard and as long as the rubber boots are intact the joints should be ok.

Robert

[wildman]

the 1/2 shaft out of a front wheel drive was my first thought. butthen i thought about the cardon joints so popular in the 4-wheel drives. it could end up being a 12 to 15 inch long shaft. it would need to be balanced. but that shouldn't be much of a problem for the driveshaft shop to do. at only 1800 rpm, there should not be that much energy in the shaft. i was not thinking of a direct connection between the engine and the generator. nobody is that good at setting things up!

i just realized that i should have posted this in the generator section--ooops, i need to pay more attention to where i am.

its pm in st louis and we are expecting another round of ice tonight. iam quickly needing to abandon my desire for the lister and will probably need to get kubota, iseki, isuzu or hercules diesel to turn a generator. its too late for this winter, but you never know what the future holds.

have a great evening- chuck

[lev-l-lok]

Chuck, a drive shaft or half shaft is the same as hard direct coupling, IE, no flex or ability to absorb shock or misalignment. I'm not sure about the load carrying potential of this, but in a pinch you could use something like an old steering shaft coupling, IE, two three legged couplings with a piece of truck tire sidewall connecting them, The steering shaft coupling would make up for any slight misalignment, but more importnatly, provide the necessary shock absorbsion. Yeah, yeah, I caught my bad, the drive shaft or half shaft will correct for misalignment, but, they require a minimum off axis of several degrees to properly self lubricate