Generator PTO Generator questions

[dennisharrison]

Just got my first tractor. A Mahindra Max 28 XL ( TractorData.com Mahindra Max 28 XL tractor information ), so much fun . Way better than my mower, the wheel barrow, a shovel, and my back!

I have a 8750 crank 7000 running gas generator that is feeding a 50 amp breaker via 6/3 to a 50 amp 4 prong twist lock male connector in a panel box. My generator is only 30 amp, but my cords and cables are all ready for me to upgrade. We recently went through hurricane Isaac and were without power for 4 days. I had to turn off the AC and a freezer to be able to run the hot water heater and pump at the same time. Didn't run the dryer, and kept my garage/shop powered down. Doing calculations, I could run everything off 12.5kw continuous. Here is where I really need someone with experience to point me in a direction:

Tractor-Driven PTO Generator - 16,000 W Max

According to what I've read online ( here and elsewhere ), this generator will provide a workable solution for me, if I have a 30hp tractor. Mine is only 28hp. Will I be able to produce at least 12.5kw out of this generator with my tractor? Also, from what I can tell - people are claiming this will use slightly less than a gallon an hour ( farm diesel isn't much more than natural gas here ). I'd really like to be able to drag his thing out to the back yard and use it to power some tools and whatnot in my projects as well, so I hope it's a workable solution.

Can anyone explain to me how to figure the power loss from the difference in hp ( the product information page says 15kw with a 30hp tractor, but don't they mean 30hp pto? ), and how to determine fuel expenditure?

I hope I'm using the proper vocabulary and have communicated my issue correctly.

Thank you, in advance, for spending any time with this request - I really do appreciate it.

--
Dennis

 

[wrooster]

Dennis,

According to what I've read online ( here and elsewhere ), this generator will provide a workable solution for me, if I have a 30hp tractor. Mine is only 28hp. Will I be able to produce at least 12.5kw out of this generator with my tractor?

For 12.5KW you'll need approximately 21HP at the input to the generator. There is an oft-quoted rule of "you need 2HP for every 1 KW" but the higher up in power you go the less accurate this rule of thumb gets. Assume in your case that you'll get about 600W for every HP and go from there. Ideally 1 HP = 746W, so using 600W instead is assuming 600W/746W = 80% conversion efficiency.

Also, from what I can tell - people are claiming this will use slightly less than a gallon an hour ( farm diesel isn't much more than natural gas here ).

For a PTO generator setup such as you are planning, assume that every KW will consume 0.1 gal per hour. So, for example, a 10KW load will require 1 gal of diesel fuel per hour.

This fuel consumption rate is somewhat higher than you might get using a diesel generator calculator, such as:
Fuel Burn Calculator - Hardy Diesel's & Equipment Inc * Diesel Generators

The reason for the discrepancy is that in the tractor PTO setup there are more mechanical conversion losses than in a direct-coupled generator setup.

I'd really like to be able to drag his thing out to the back yard and use it to power some tools and whatnot in my projects as well, so I hope it's a workable solution.

I do the same.

Can anyone explain to me how to figure the power loss from the difference in hp ( the product information page says 15kw with a 30hp tractor, but don't they mean 30hp pto? ), and how to determine fuel expenditure?

The only number that matters is the PTO shaft HP -- this is the input to the generator head. In general, for HST tractors the PTO output will be about 75-80% of the engine HP; and for geared tractors the PTO output will be about 85% of the engine HP.

Wrooster

 

[newbury]

<snip> We recently went through hurricane Isaac and were without power for 4 days. I had to turn off the AC and a freezer to be able to run the hot water heater and pump at the same time. Didn't run the dryer, and kept my garage/shop powered down. Doing calculations, I could run everything off 12.5kw continuous.

Welcome aboard, sorry to hear about Isaac, I sat in NE Mississippi waiting for the rain to come.

Here is where I really need someone with experience to point me in a direction:

Tractor-Driven PTO Generator - 16,000 W Max

First of all, you want something safe to sit on correct? I think of a stool for safety, 3 legs to stand on.

I've a small 0.8KW HF generator, 2 stroke.
Another small 6KW gas generator.
And a 12KW Winco PTO powered generator.

Harbor Freight is having a sale on their 800W generator (a tiny hand carried two stroke) for $80 (regular price $180) at their parking lot sale Oct12-14. These are CHEAP CHINESE generators, give them good fuel mix with Seafoam and they run fine.

According to what I've read online ( here and elsewhere ), this generator will provide a workable solution for me, if I have a 30hp tractor. Mine is only 28hp. Will I be able to produce at least 12.5kw out of this generator with my tractor? Also, from what I can tell - people are claiming this will use slightly less than a gallon an hour ( farm diesel isn't much more than natural gas here ). I'd really like to be able to drag his thing out to the back yard and use it to power some tools and whatnot in my projects as well, so I hope it's a workable solution.

Yup, probably, and sounds like a workable solution. See prior poster.

<snip>
I hope I'm using the proper vocabulary and have communicated my issue correctly.

Thank you, in advance, for spending any time with this request - I really do appreciate it.

Darn clear. HF is routinely dumped on. There is another thread here on their generators. My Winco 12KW went for $600 on CL. I looked for about a year. Winco's smallest PTO generator now seems to be 15KW rate for about $2,200 new.


Just be prepared for a lot of flack re:you'll need your tractor for other things.

 

[Eyecatcher]

A couple of things you need to look for prior to buying. Copper windings, especially in himid areas like where we live, 1800 rpm. 3600 units tend to wear faster, and vibrate more. How the generator is mounted. I bought tiger power, and it's on a trailer w/full size tires, makes it pretty easy to move around. PTO shaft mounts on a built in carrier when not in use.

 

[daybreak1998]

Howdy,
To put a few things into perspective
Start your tractor and place it in the location where you would have it running a pto generator. Now engage the pto and bring it up to speed. (PTO shaft speed 540rpm) Now, leave it sit there running. Walk around your property, walk around inside, lie down in bed and listen. That is about the sound level. Next, the electrical connection. You have a perfect upgrade route with wiring large from the start. The PTO generator quest really boils down to approximatily 1.82hp per 1kw produced. It is just much easier to explain and tell folks 2hp per kw produced. But, the same thing applies for the true tractor rating. A tractor could have a very agressive hp rating which might be absolute perfect conditions, to make that mythological rating. or the rating could be conservative. And like most generator users (all styles) no one really wants to run a generator at 100% capacity. You could actually run a 20-50kw pto generator. You would just be limited to approx. 15,000-16,000 kw produced.

Smaller PTO generators will probably have a 2 pole alternator end. Cheaper to make, and they spin at 3600rpm to produce 60Mhz 240. Most standalone gas generators out there, have 2 pole alternators, since the little gas engine is spinning at 3600rpm. (direct-coupled) Since the PTO shaft of the tractor is spinning at 540rpm, you then have a gear box, which translates that 540 speed into 3600rpm. Here you have another variable for noise. That little unit spinning at 3600rpm. Larger PTO generators can be found with 4-pole alternators which means they sping at 1800rpm to produce 60Mhz 240. Direct coupled diesel genset work with a diesel engine spinning at 1800 and alterator at 1800.
Fuel usage= that will very with load. What mileage do you get driving a 100 mile round trip with no stops? Now make that trip towing a 8000lb trailer? same mileage? Having the extra overhead from a generator standpoint is good. There are lots of members here which can give you feedback about what unit your looking at purchasing too. You could then sell your current genset, or keep it as a backup too.

 

[dex3361]

I ordered the same generator that you are looking at and it came in with an issue. A couple of the rubber vibration dampeners were damaged(dont know how) and I have replacements on the way. I saw this PTO unit from Rural King and it looks like the same unit with a different base. Both units come with the pto shaft. I took the end off of the HF generator and it has copper windings. Just a little info to help in your decision making.

 

[Ductape]

Looks you got your just in time....... they are on back-order again.

 

[dex3361]

Looks you got your just in time....... they are on back-order again.

Your right, I didn't notice that.

 

[ctgoldwing]

I went a different route. Last year here in Connecticut we got hit with 2 big electrical outage events - a summer storm and then an unbelieveably early heavy snow storm in October. Both time we were without power for 4-5 days. I was looking for a pto driven generator but after those two experiences I decided on a standalone solution.

In both storms I really needed the tractor for cleanup - especially moving & chipping downed tree & limbs. My son who live in Maryland & I both bid on & got government surplus diesel generators from Fort Meade. They are MEP-003A's - 10KW, 4 cylinder, Onan, air cooled REALLY heavy duty units. Mine had 2 hours on the clock since overhaul, Adam's had a couple more. They can supply 10-12KW tho I have to say I have a hard time loading to anywhere near that.

As I have a 400 amp service in my house I searched & searched on Ebay until I finally found a 400 amp manual transfer switch for $250 - brand new The genset has been wired in now for almost a year and we haven't lost power for a second. I just get to start it once a month to thoroughly warm it up. Adam got to run his for almost a week this year when that freak storm went through his area.

btw they both came on new 3/4 ton trailers. I am debating selling the trailer or keeping it. Lucky they did becaue Adam was able to simply tow mine up to me from MD to CT.

The government is always auctioning these things off

Here I try to get the genset off the trailer - L3400 just too little




Had to get someone with a bigger toy

 

[Rock knocker]

In both storms I really needed the tractor for cleanup - especially moving & chipping downed tree & limbs. My son who live in Maryland & I both bid on & got government surplus diesel generators from Fort Meade. They are MEP-003A's - 10KW, 4 cylinder, Onan, air cooled REALLY heavy duty units. Mine had 2 hours on the clock since overhaul, Adam's had a couple more. They can supply 10-12KW tho I have to say I have a hard time loading to anywhere near that.

Here I try to get the genset off the trailer - L3400 just too little

View attachment 279001


Had to get someone with a bigger toy
View attachment 279002

Those are really nice. How much did they set you back? I would guess Uncle Sam rebuilt them after they had about 16 hours on them.

What voltages do they put out?

At work, in 1995, we bought several Army surplus gas-powered generators which dated to the Vietnam era. All had less that 20 hours on the clock. The voltages were really wierd: three phase 240, three phase 120 and a couple of other configurations I can't recall.

And like you, we got the trailers, which are coveted by the OHV set