PTO generator at max torque or max HP?

[workinonit]

+1

 

[rScotty]

Maybe you saw it, but you didn't agree with it, so you discounted it.

And, it depends on what your definition is, of a "simple" stand alone it...

SR

Probably. But for us this isn't a theoretical discussion. Power outages of 3 or 4 days happen often in these mountains. So I thought to share some thoughts because we have a lot of knowledge dealing with power outages. The reason I prefer a stand alone generator is based on experience.

What I mean by "simple" is that the generator is simply a generator. No other function.
Things that make the Honda's local favorites are how quiet they are and how fuel efficient. They are very sophisticatd. It's remarkable how quiet they are. I can hear it enough to tell it is running, but can hold a normal conversaton while standing next to ours. Outside on the porch, it doesn't make enough noise to hear inside the house.

Downside to the Honda is that they cost twice to three times what the louder generators do. A neighbor has one from Home Depot that you can hear everywhere on his property and inside as well. It also uses several times the fuel that the Honda does.

The arguments in favor of the Tractor PTO don't work for us, because the tractors ares needed to deal with whatever caused the power outage in the first place.
rScotty

 

[can do]

Probably. But for us this isn't a theoretical discussion. Power outages of 3 or 4 days happen often in these mountains. So I thought to share some thoughts because we have a lot of knowledge dealing with power outages. The reason I prefer a stand alone generator is based on experience.

What I mean by "simple" is that the generator is simply a generator. No other function.
Things that make the Honda's local favorites are how quiet they are and how fuel efficient. They are very sophisticatd. It's remarkable how quiet they are. I can hear it enough to tell it is running, but can hold a normal conversaton while standing next to ours. Outside on the porch, it doesn't make enough noise to hear inside the house.

Downside to the Honda is that they cost twice to three times what the louder generators do. A neighbor has one from Home Depot that you can hear everywhere on his property and inside as well. It also uses several times the fuel that the Honda does.

The arguments in favor of the Tractor PTO don't work for us, because the tractors ares needed to deal with whatever caused the power outage in the first place.
rScotty

That's what I ended up going with a portable Generac GP17500E & I didn't want to go this route because it's another engine that I will need to pm every year! That being said the better half told me that I don't want to be using the tractor for that purpose . & this generator will take care of all my needs with a 30 HP gas engine , 17,500 rated & 26,250 surge watts. Drawbacks 16 gallon tank & a 10 hour run time & the unit weighs 400 lbs. But I like the idea of it being portable if I need to work somewhere else on the property & I don't have electricity.& both tractors will be doing what I bought them for.

 

[CobyRupert]

Whatever gives you the right voltage and cycles.

That would be a some point very close to 540 PTO rpm. He can get 540 PTO rpm with both settings.
Question is, which engine rpms (at 540 PTO rpms) delivers most stable voltage.
Most likely the higher engine rpm will be more stable, but it “could” depend on how a combination of load characteristics (especially motor starting characteristics, and sequencing) align with motor and generator systems rotational mass, engine horsepower, torque curves, and governor response times.

Caterpillar use to have on-line generator sizing software where you could play with with loads (add and delete them), change motor and generator sizing and types, change load sequencing, etc.. and it would calculate voltage dips magnitudes and durations.

What you realize, is if you’re sizing a generator based on just the expected running load, you better oversize it by a lot to account for the other factors you’re ignoring.
Or manage your loads closely.

 

[California]

Most likely the higher engine rpm will be more stable, but it “could” depend ....

Higher engine RPM will have more engine flywheel inertia to resist a sudden load.

 

[Sawyer Rob]

Higher engine RPM will have more engine flywheel inertia to resist a sudden load.

Because of gearing TO the pto, the higher RPM will have more torque to the pto/generator to cover heavy loads.

SR

 

[5030]

Probably. But for us this isn't a theoretical discussion. Power outages of 3 or 4 days happen often in these mountains. So I thought to share some thoughts because we have a lot of knowledge dealing with power outages. The reason I prefer a stand alone generator is based on experience.

What I mean by "simple" is that the generator is simply a generator. No other function.
Things that make the Honda's local favorites are how quiet they are and how fuel efficient. They are very sophisticatd. It's remarkable how quiet they are. I can hear it enough to tell it is running, but can hold a normal conversaton while standing next to ours. Outside on the porch, it doesn't make enough noise to hear inside the house.

Downside to the Honda is that they cost twice to three times what the louder generators do. A neighbor has one from Home Depot that you can hear everywhere on his property and inside as well. It also uses several times the fuel that the Honda does.

The arguments in favor of the Tractor PTO don't work for us, because the tractors ares needed to deal with whatever caused the power outage in the first place.
rScotty

I don't have any noise issues as my standby is out by the shop which is about 350 feet from the house and being a well muffled diesel and I can only barely hear the turbocharger whine. Myself, I'd never have a tractor driven pto genny. I have no desire to one, tie up a tractor and 2, run any of my tractors for hours on end at rated pto rpm. Finally, I don't want the added inconvenience of hooking up and unhooking a pto generator every time the power fails. Much easier for me to let the standby assume the load and do an automatic transfer of current completely hands off. All the controls and transfer switchgear are inside the shop out of the weather. if I'm not home and the utility fails, my wife don't have to worry either. Peace of mind is worth everything to us.

 

[Smokeydog]

Tractor diesel governors are not like engine powered generators governors that control engine rpm to maintain a certain rpm and Hz cycles. Tractor diesel governors really only work at low or too high rpm. Ever mow sloped field? Rpm changes down and up hill. Can lower or increase throttle to maintain rpm but is not automatic or governored. You can maintain voltage and hertz pretty well and some loads like heaters and motors are tolerant to fluctuations. This does require some input from the operator. They do have a certain applications.

Stand alone generator generators can maintain clean power easily.

We have a 30+ year old Miller welder/generator gal/hr and 17 year old Yamaha 2400 watt inverter 1.75gal/8hr generator. Latter was run for 4 hours, refrigerator, freezer, lights, internet tv, wood stove fan and medical equipment last week. Our lifestyle and requirements make having back up power necessary.

There are many options and solutions.

 

[Hall00]

I don't have any noise issues as my standby is out by the shop which is about 350 feet from the house and being a well muffled diesel and I can only barely hear the turbocharger whine. Myself, I'd never have a tractor driven pto genny. I have no desire to one, tie up a tractor and 2, run any of my tractors for hours on end at rated pto rpm. Finally, I don't want the added inconvenience of hooking up and unhooking a pto generator every time the power fails. Much easier for me to let the standby assume the load and do an automatic transfer of current completely hands off. All the controls and transfer switchgear are inside the shop out of the weather. if I'm not home and the utility fails, my wife don't have to worry either. Peace of mind is worth everything to us.

Pointless as this thread is about pto gennys and not standalones.

 

[Sawyer Rob]

Tractor diesel governors are not like engine powered generators governors that control engine rpm to maintain a certain rpm and Hz cycles. Tractor diesel governors really only work at low or too high rpm. Ever mow sloped field? Rpm changes down and up hill. Can lower or increase throttle to maintain rpm but is not automatic or governored.

That hasn't been MY experience. The only tractors that lose rpm on hills while mowing, are the tractors that are under powered or don't have good low-end torque. OR you are in too high of a gear, for that slope.

SR

 

[LouNY]

Amazing simply amazing I don't know how the various tractors I've had running PTO generators ever managed to work.
From way back when the Farmall 400 was running my fathers PTO generator for all the dairy farm loads from not much to almost maxing it out during feeding from the upright silos with the bulk tank compressors running to cool milk.
To putting a 7220 IH Magnum on my little 25 KW one day when my tractor acted up.
My old IH 350 utility ran good and stable, the Oliver 1550 never had a hiccup, the IH 574 will run fine and the Branson 8050 will run good stable power in the 540E mode.
Less then 2 Hz variance from no load to full load.
I'm not afraid to run my tractors on loads with no one present, if one goes down for some reason it would have sooner or later anyways.
The governors on all those tractors handled the varying loads just fine.
The only time I have had governors not be responsive enough was running a 540 generator on the 1000 rpm shaft at half throttle,
then the 574 didn't maintain the regulation I desired.
A 1086 did fine in that situation allong with the Magnums.

 

[CobyRupert]

Because of gearing TO the pto, the higher RPM will have more torque to the pto/generator to cover heavy loads.

SR

Yes, but....
… what if the engine’s torque curve drops off more at the higher rpm than the torque lost using the PTO gearing at lower engine rpm?
Doesn’t it now depend on the characteristics of the load being added? That is, the lower rpm engine only has to drop a few rpms for engine to recover with maximum torque, whereas the high rev engine will drop many more rpm, or dip for a longer period of time, to recover with less torque (because of where you’re at on torque curve)?
Sure, chances are a perfect storm won’t aligned like this, but….?

 

[Sawyer Rob]

The engine is making more HP at the higher rpm, so it holds its speed better at the higher rpm.

One of my tractors makes 60 hp at pto speed, but it makes 70 at max rpm, and that's on a dyno, not some book number.

SR

 

[npalen]

Seems like this discussion is ripe for someone to propose a frequency controlled governor retrofit.

 

[workinonit]

Tractor diesel governors are not like engine powered generators governors that control engine rpm to maintain a certain rpm and Hz cycles. Tractor diesel governors really only work at low or too high rpm. Ever mow sloped field? Rpm changes down and up hill. Can lower or increase throttle to maintain rpm but is not automatic or governored. You can maintain voltage and hertz pretty well and some loads like heaters and motors are tolerant to fluctuations. This does require some input from the operator. They do have a certain applications.

Stand alone generator generators can maintain clean power easily.

We have a 30+ year old Miller welder/generator gal/hr and 17 year old Yamaha 2400 watt inverter 1.75gal/8hr generator. Latter was run for 4 hours, refrigerator, freezer, lights, internet tv, wood stove fan and medical equipment last week. Our lifestyle and requirements make having back up power necessary.

There are many options and solutions.

This is just simply not true if the tractor is large enough for the load. And if diesels didn't control gens well, they wouldn't be so popular on standby gens. Here's the bottom line. There are a lot of you that for whatever reason don't like PTO generators. That's fine, but PTO gens work really well. In my opinion they are much better than standbys because I know my tractor will start, the standby you never know. Yes, it's not automatic but I really don't want it to be. I like to be there and know what's going on before I tie my gen to my houise load. It all boils down to the fact that it's an opinion and goodness knows, everyone has three of those.

 

[Smokeydog]

This is just simply not true if the tractor is large enough for the load. And if diesels didn't control gens well, they wouldn't be so popular on standby gens. Here's the bottom line. There are a lot of you that for whatever reason don't like PTO generators. That's fine, but PTO gens work really well. In my opinion they are much better than standbys because I know my tractor will start, the standby you never know. Yes, it's not automatic but I really don't want it to be. I like to be there and know what's going on before I tie my gen to my houise load. It all boils down to the fact that it's an opinion and goodness knows, everyone has three of those.

If pto generator works for you that’s great! Sized to a tractor and loads required. Worse is low hp tractors and small generators.

Diesel engine generator governors are different than what’s on tractors so your point is null.

Local sawmill uses 3phase diesel generator to power their mill. Owner was talking on looking for a replacement because of 15,000+ hours. 40Kw. Had another genset for a planer and resaw operation. I asked how about a pto generator? He had lots of tractors and existing fuel supply? He said we tried that, don’t work, can’t take the variable loads, burnt motors, ate fuel, it’s over there in the shed if you want it. Granted he was not your typical backup power user.

Pto generators have their place. Can get them at scrap prices at auctions around here. If they satisfy your need that’s great. I tend to now measure success in decades of use.

Sharing experiences helps us all. Your experience is valuable.

 

[LouNY]

I have to wonder how many of your portable or even whole house generators are 25 years old,
I know of several pto generators well over 20 years old and still in service.
As far as governors a tractor governor in good shape that hasn't had someone monkey with does a good job
holding constant rpm with a varying load.

To each his own, I like my pto generator and it has done an excellent job for me for well over 20 years.

 

[JethroB]

Seems like this discussion is ripe for someone to propose a frequency controlled governor retrofit.

Let’s add tractor water temp & oil pressure monitoring while we are at it.

 

[workinonit]

If pto generator works for you that’s great! Sized to a tractor and loads required. Worse is low hp tractors and small generators.

Diesel engine generator governors are different than what’s on tractors so your point is null.

Local sawmill uses 3phase diesel generator to power their mill. Owner was talking on looking for a replacement because of 15,000+ hours. 40Kw. Had another genset for a planer and resaw operation. I asked how about a pto generator? He had lots of tractors and existing fuel supply? He said we tried that, don’t work, can’t take the variable loads, burnt motors, ate fuel, it’s over there in the shed if you want it. Granted he was not your typical backup power user.

Pto generators have their place. Can get them at scrap prices at auctions around here. If they satisfy your need that’s great. I tend to now measure success in decades of use.

Sharing experiences helps us all. Your experience is valuable.

Funny how the best gen manufacturers make diesel gensets and they are preferred by most buyers. Experience, I've owned one since 1998 and used it for lots of things. It's mounted on a trailer that I hook behind my tractor and my welder and a small air compressor will fit on. I've run it behind 2 different JD tractors and both ran it flawlessly. The tractors control it to within 2 to 3 volts. Maybe the ones you are aware of aren't sized properly or are attached to tractors that don't control loads very well. I was stating my opinion but what you wrote was just simply not the truth based on my many hours of experience.

 

[California]

Lets not forget the OP was considering using a small tractor to run a PTO generator that is rated to need more horsepower than he has available, so limiting the load and the effectiveness of the tractor's governor are the major considerations in his application.