The engine runs ~6x faster than a PTO,,,,

 

So maybe do a pto shaft to a pulley type of deal?

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People have done it but, IMO, it isn't worth the trouble. It's easy enough to find blown generators on Craigslist that have good engines and just do a swap.

The generator head on that portable generator connects to the motor using a tapered shaft. If you don't have you're own machine shop you'll have to go find one that can make you a tapered-to-straight shaft that you can connect to the gen head and then mount a pulley on. Then you've got to figure out how to mount the whole thing and figure out the PTO shaft-to-pulley setup.

Don't get me wrong. It could be a fun project to play with but it won't be "easy".

I've got a generator in my shed that has less than 6 hours on it but it's got a blown generator head so I'm in sort of the opposite position you're in. If I can ever find a good 5500 watt gen head for it for short $$ I'll get it running again.

 

Time for a deal



It ain't that far from Smithfield Va to Berlin Md. . . Maybe y'all should get together.

Treefarmer

 

My brother had troubles with the carb on his generator,,,
he ordered a new gen set from Amazon, it came in two days, the old one went to the landfill.

I am afraid to admit,,, we are truly in a disposable society anymore.
He could not get the carb, the gen set was about 6 years old.

The belt/pulley will not work for any close voltage needs,
the slippage will be so great, the voltage will vary with the load too much.

You could use it for lights, run your saw, etc,,,
keep the TV and computers turned off.
I would not plug my refrig into the pulley/belt generator.

My brother lives in Smithfield, coincidentally,,,
you didn't get my brother's from the landfill, did you!!?? :dunno:

:laugh:

 

Umm, you guys don't give belts enough credit.

My air compressor has a 5hp motor connected via 2 V-belts I've never touched in 9 years of ownership. My compressor is running about an hour a day when I'm running production. I use air to cool my cutters and clear chips. It runs a lot!

Getting the right amount of belt/sheave contact is important for belt life and power transfer, but it's not hard to do. Plus, belts are cheap and quiet means of power transmission.

 

Umm, you guys don't give belts enough credit.

I did not come up with the belt/pulley concept, but,
have heard it from electrical guys with WAY more smarts than I can imagine,,,

They say direct drive, gear reduction, or,,, inverter technology.

If I had the :gizmo:,,, I would own a 10KW inverter equipped gen set.

 

Gears are way higher noise and maintenence. My experience is that electricians make terrible mechanical engineers. :lol:

Btw, my air compressor was made in 1986 and was bought out of a machine shop auction. Could be the original belts for all I know.

Inverters still spin an armature. They just make DC and convert it into AC. The false sine wave created by PWM lets them run more load out of less inputs. It's a more efficient method of generation now that IGBT's are cheap enough. Essentially it's a high wattage 120v stereo amplifier, but it only makes 60hz.

 

Gears are way higher noise and maintenence. My experience is that electricians make terrible mechanical engineers. :lol:

Btw, my air compressor was made in 1986 and was bought out of a machine shop auction. Could be the original belts for all I know.

Compressors aren't really an apt comparison here. If the belts stretch or slip a little that just means it will take an extra second or two for the compressor to do it's job of getting the tank up to full pressure. On a generator, a stretched belt or slipping means you drop from 60 Hz to 50Hz or pop up to 70Hz. Frequency fluctuations are not good!

That's not to say you can't run a generator off of a pulley/belt system. You just have to add on the necessary "stuff" so you can keep track of things. Most the the Home Cheapo style generators don't come with a frequency meter to monitor the output. But the systems that are belt drive usually do so you can tell if things need to be adjusted. The better systems even connect the frequency counter to a controller to run a governor on the drive motor so that if the frequency drops the engine RPM speeds up or slows down to compensate.

But there is another problem here in that the type of gen head he's got is only a single bearing unit. The bearing is in the rear and shaft from the motor (which has it's own bearings) is supporting the front end. To run off a belt, you really need a gen head with dual bearings so that both ends of the armature are supported.

 

If you were concerned about belt slippage, you could use a cogged belt and pulleys. It would require some custom machine work to put it all together and may cost more than a replacement engine, but it could be done.

 

Just throwing this out for thought: Belt vs. Gear drive...

This is the drive assembly of a helicopter main rotor. This is NOT an UNCOMMON form of power transmission. You know these belts are mighty important to the people riding in the helicopter and the people watching it fly overhead!

I wouldn't be afraid to hookup a belt drive as long as you have the right belts and pulley combinations.

 

Just throwing this out for thought: Belt vs. Gear drive...

This is the drive assembly of a helicopter main rotor. This is NOT an UNCOMMON form of power transmission. You know these belts are mighty important to the people riding in the helicopter and the people watching it fly overhead!

I wouldn't be afraid to hookup a belt drive as long as you have the right belts and pulley combinations.

View attachment 257897

Is that drive setup for the tail rotor?

 

If I had to do a reduction style system I'd do a chain drive... just makes more sense

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What?? Can't hear you over the chain whine.

Belt slip on my compressor would cause wear that would've lead to failure by now. It just doesn't happen. Belts are durable, quiet, light weight, and cheap.

Proper support of the rotor is a given. You don't often find stuff you can remove major components and be ready to go with another completely different configuration. It wouldn't be a monumental task to adapt a second bearing. Well, not if you have the right skills and equipment.

 

:laugh: been following along on this thread, it is in deed quite interesting to say the least. i learn a lot off of these type threads, but if ur gas motor blew up, why or have u just priced another motor?:dunno:

or are u just barnstorming for other ideas! i'm not trying to weigh u either way-just curious, if u figured u might just make u something, no one else has done-that's all:thumbup1gif: good luck to u, and i will continue to follow along to see what u do in the end.:munch:

 

I have also have been watching this thread and the points of view are very interesting.
It is true that your generator is not designed for the side loading that a belt drive will exert. Therefore, if you do a belt drive, you will need to drive the generator off pillow block bearing supported jackshafts. Not impossible, just more :gizmo:

Another thing to consider is, you would need to engineer the ratio between the input (drive) speed of 540 RPM up to 3600 RPM output speed. This will require a 1 : 6.6 increase ratio. To do this kind of ratio with a belt drive, it would take two drives connected back to back. If one drive is used and the output drive pulley (generator end) is 4", the input pulley (PTO end) would need to be 26.4" in diameter. This is not practical.

Also, the comparison between an air compressor drive and the drive required for a generator is not an apples to apples comparison. An air compressor drive is a ratio reduction between the motor and compressor. On a PTO driven generator, the drive is a ratio increase between the PTO and the generator.

So, about the only way to practically get this kind of ratio increase is with a gearbox. The problem is, most generator PTO gearboxes are 1 : 3.3 ratio. This ratio will result in an 1800 RPM output which is what many PTO generators run at. To run you generator at 3600 RPM, you would need a 1 : 6.6 ratio gearbox.

Bottom line and IMO, after you spend all the time, effort and $$$$'s trying to put all this together, you could most likely buy a new engine for the generator. And even after you would get this project done, you have to ask, will it be dependable. If you have to work on it every time you need to use it, it is not worth the effort.