X744 PTO Generator

[Gonerafting]

Probably an old subject, but I cannot find the definitive answer. John Deere once sold a PTO Generator for the X700 series tractor. My understand is you need 2HP per 1KW and that would mean you need 20HP at the PTO to operate a 10KW. My research indicates the X700 series produces 18HP at the PTO. Every manufacturer I have contacted have stated that 18HP is not adequate to run a 10KW Generator. Did John Deere stop selling the PTO Generator due to issues with inadequate PTO HP or do they underrate the HP at 18HP? John Deere just refers me to the Dealer and that really has not been helpful. Does anyone have a 10KW Generator and does it operate properly with a X700? Or, does anyone know of a PTO generator rated at 8KW or 9KW? I know Northern Tool makes a 7.2 KW PTO Generator, but would prefer 10KW, 9KW or 8KW. So, far I have found no one who can answer the question why John Deere sold a 10KW Generator at one time if the X700 only produces 18HP at the PTO.

 

[beenthere]

If you just use 9KW, wouldn't the 18hp work even tho it is a 10KW ?? i.e. I'm thinking it will work

 

[Sawyer Rob]

You need 2hp per kw if you want MAX out of the generator...

IF you don't need MAX, a smaller tractor will run the gen set, you just can't pull MAX out of it.

I run a 15kw pto gen set with a Kubota that has 12.5hp on the pto... I can easily pull 6kw out of the generator with THAT tractor, if I need more power, I just put a bigger tractor in front of it.

SR

 

[Gonerafting]

You need 2hp per kw if you want MAX out of the generator...

IF you don't need MAX, a smaller tractor will run the gen set, you just can't pull MAX out of it.

I run a 15kw pto gen set with a Kubota that has 12.5hp on the pto... I can easily pull 6kw out of the generator with THAT tractor, if I need more power, I just put a bigger tractor in front of it.

SR

My understanding is you can cause damage from not having 2hp per KW to appliances, but I could be wrong. WINCO stated they would not advise it. I actually chatted with two other companies who advised not to run with less than 2hp per KW. If I can get by with a 10KW generator, that would meet all my needs.

 

[zzvyb6]

I easily run my 50kW Winpower off a pto adaptor on my 22 h.p. JD F-935 lawn mower. Of course it will run it, just not up to 50kW. That would take a 100 hp tractor (theoretically). With normal power needs, it never hits the governor.

 

[Sawyer Rob]

My understanding is you can cause damage from not having 2hp per KW to appliances, but I could be wrong. WINCO stated they would not advise it. I actually chatted with two other companies who advised not to run with less than 2hp per KW. If I can get by with a 10KW generator, that would meet all my needs.

My pto generator IS a Winco... It's been behind my small Kubota many MANY times, it works perfectly, UP TO it's max pto hp...

SR

 

[Gonerafting]

I easily run my 50kW Winpower off a pto adaptor on my 22 h.p. JD F-935 lawn mower. Of course it will run it, just not up to 50kW. That would take a 100 hp tractor (theoretically). With normal power needs, it never hits the governor.

I guess, the manufacturers are like everyone else and concern for legal issues and probably being sued if one cannot get the maximum output. I reality, I'm fine with between 8KW and 9KW out of a 18HP PTO. I appreciate the responses. I also assume John Deere has underrated the HP of the X744 PTO. As previously mentioned, they once sold there own 10kw generator for the X700 series. But, who knows who really manufactured it. Everyone has to be concerned about sue crazy folks out there.

 

[Sawyer Rob]

Last fall something happened to the power from the pole, going under ground to my shop. (different meter from my house) Anyway, I had some welding I needed to get done, so as the pto generator was already in the shop, I opened the big doors, hooked the above Kubota to the gen, hooked the gen to the breaker box and powered the shop...

The Kubota hummed away as I got all of my welding done, and had power for lights and side grinding at the same time. It's REALLY handy to be able to use my gen set in different places...

SR

 

[Dave M7040]

Notice on the literature supplied by Winco, some attention has to be done to avoid the trailer and generator starting to rotate as engine torque builds up.

Dave M7040

 

[Gonerafting]

The X744 rear PTO at 18hp runs at 540 rpm. I notice the Winco 10kw runs at 515 rpm with 20hp. So, given the 18hp will run the generator, not at 100%, is there are in running the generator at 540rpm with the X744 running at full throttle to get the maximum output? Thanks for all the helpful responses, I really appreciate the information. I would be buying the Winco Trailer to go along with the generator.

 

[jenkinsph]

The X744 rear PTO at 18hp runs at 540 rpm. I notice the Winco 10kw runs at 515 rpm with 20hp. So, given the 18hp will run the generator, not at 100%, is there are in running the generator at 540rpm with the X744 running at full throttle to get the maximum output? Thanks for all the helpful responses, I really appreciate the information. I would be buying the Winco Trailer to go along with the generator.

Hard to understand your question but if the Winco is rated for 515 rpm you may not be able to get use of the maximum pto hp. output from your x744. It won't change things much though and is not something I would be concerned with. I would keep the load maximum to about 7.5kw for sustained use or do the calculations with the x744 operating at 85% loading. The generator you use will require a constant speed and needs to be held close to this for 60 cycle power. When you load an engine down excessively it has a hard time maintaining proper rpm's.

For most generators running a home the load varies quite a bit and usually you will be using a lot less than 5 kw at any given time. You should be able to handle a power outage with a little management of appliances. If you have an all electric home I would not try to run the clothes dryer, water heater, well pump and furnace at the same time. Before buying the generator I recommend you name plate and list the various loads you require to run, you may need a larger genset to fill your needs. An electric furnace can easily require 20kw just for the strip heaters. A gas or oil fired furnace on the other hand can be run on about 1kw.

Just my opinion but I think it is good for some people to experience what it is like not to have all the utilities available. It can be an eye opening experience and a good education, learning how to get by without having everything available to power their life style.

 

[Dave M7040]

The rpm's are a critical factor in all of this.
The rpm's determine the frequency of the electricity produced.
Most lower cost generator heads are two pole which means the actual unit is turning 3,600 rpm to produce 60 cycle power which is the North American Standard.

European standard is 50 cycle so they run their generators at a lower speed than we do.
There are gears at the generator end of the pto shaft to speed up the 540 rpm to the 3,600.
Some tractor have a two speed rear pto. Don't go using a speed different than the one specified as you will fry the brains out of anything you plug into it by producing a higher frequency. You wont produce any more power.

Large commercial level generators with their own engine are 4 pole units and run at 1,800 rpm to produce 60 cycle power.

The new style inverter generators that are being sold in low outputs, say 4,000 watts, manage the generation of frequency electronically and that is why they are not so noisy as their engines are running at a lower than 3,600 rpm.

Dave M7040

 

[Sawyer Rob]

My Winco does not run at 515rpm, and I don't think it matters anyway.

PTO gen sets have a "meter" on them, you engage the pto and increase the rpm until the meter is where it needs to be.

I don't worry about the what the rpm is, I just keep the meter where it's suppose to be and start turning on the loads to the gen set.

IF the tractor isn't over loaded, the tractors governor will keep the rpm where it needs to be.

SR

 

[beenthere]

SR
:thumbsup:

 

[jenkinsph]

My Winco does not run at 515rpm, and I don't think it matters anyway.

PTO gen sets have a "meter" on them, you engage the pto and increase the rpm until the meter is where it needs to be.

I don't worry about the what the rpm is, I just keep the meter where it's suppose to be and start turning on the loads to the gen set.

IF the tractor isn't over loaded, the tractors governor will keep the rpm where it needs to be.

SR

I like simple answers too but that does not explain answers to the questions posed here. The OP is trying to get a handle on what he can expect to get out of his mower/generator combo. Before he buys one.

 

[Sawyer Rob]

I like simple answers too but that does not explain answers to the questions posed here. The OP is trying to get a handle on what he can expect to get out of his mower/generator combo. Before he buys one.

#3 answered that, no need to repeat it here!!

Now he's trying to complicate things by asking "altered" questions, so I have to alter the answer too!

SR

 

[Dave M7040]

in 1998 in eastern Canada and north eastern USA, a massive ice storm saw power down for weeks to months.
When utility power was restored, there was a sudden realization of the amount of electrical equipment damage that had been done to electrical motors that were powered by backup generators. The Ontario provincial government undertook a study to identify the causes of this substantial damage as farmers were the most affected.

Many people don't like complicated technical answers for many reasons and to those whose mindset is like this I apologize for veering into the technical a bit.

PTO driven generators ability to deliver high quality power is influenced by the engine governor

Diesel engines used for farm tractor operations have variable speed governors designed to control engine speed at any speed selected by the operator, between low idle and high idle. The disadvantage of this type of governor for generator operation is the change in engine speed that follows any change in load.

Engines used specifically for genset operation are designed with a constant speed governor that will maintain a constant engine speed even with changes in load.

Tractors with a "high torque rise" will generally perform better than those with a relatively flat torque curve. Electronically-controlled engines are now available, allowing the operator to choose the governor characteristics required for a specific application. Farm equipment dealers can supply specific torque curves for their tractors.

The frequency stability is a very very important aspect of quality power and if your engine governor is not able to maintain a constant speed in the face of varying loads and do this instantaneously you might be damaging expensive items like heat pump compressors or AC compressors.

Engines used specifically for genset operation are designed with a constant speed governor that will maintain a constant engine speed even with changes in load.

Tractors with a "high torque rise" will generally perform better than those with a relatively flat torque curve. Electronically-controlled engines are now available, allowing the operator to choose the governor characteristics required for a specific application. Farm equipment dealers can supply specific torque curves for their tractors.
Most tractor instrument panels include a tachometer to indicate the engine speed required to deliver 540 (or 1000) PTO rpm. These tachometers were extremely inaccurate. For the requested speed of 540 rpm, actual speeds ranged from 450 rpm (-17%) to 600 rpm (+11%). These extremes, if unadjusted while operating the generator, would result in frequency variations from a low of 50 Hz to a high of 67 Hz.
If running incandescent light bulbs and heating with resistance heat either the home or hot water then you have nothing to worry about.

Dave M7040

 

[Gonerafting]

I'm thinking of going with the Northern 7.2KW that runs at 540 rpm and "requires" a 14hp PTO. It will meet the needs for my house and seems less complicated since my X744 PTO is 18hp and 540 rpm. I found this thread very informative and I think it will be helpful to many in the decision making process of purchasing a PTO generator. I could go with a larger generator, but I always do overkill and need to learn not to do that.

 

[Amvcane]

Just curious, have you thought about getting a stand alone generator? Something like a 6500 to 7500 watt Generac for example. No hours or wear on your tractor and cost a lot less money. Have you weighed the pros and cons?
I feel it is important to size the generator to your use. Three years ago, I purchased a 10,500 continuous watt, used, Northstar, 20hp Honda, with maybe 20 hrs on it for $800. My thinking was to use the engine in my JD 318 if the Onan rebuild didn't go well. Rebuild went well. Now I have a generator which will run everything in the house, elec. stove, dryer, well pump. The generator is big, heavy, difficult to move around and uses a lot of fuel. But the price was right. I really could use a 4,500 to 5,500 watt generator. My only real demand is the surge current to turn on the 220V 3/4 hp well pump.

 

[Sawyer Rob]

In THIS case, "some" over kill means it will last longer...

Keeping a generator at 80% or less load will make it run cooler and that = longer lasting, so size accordantly...

SR