PTO generator at max torque or max HP?

[mini14]

I have 2 gennys, i hate to waste resources so i operate them load dependently one is a 5500 watt gas honda the other is a 1600 watt inverter chinese made throwaway that runs great. the inverter genny will run 8-10 hrs on 1 gal. just a few lights and power the fridge all day/night long, i rarely use the 5500 watt one to power the whole house minus the ac. it just eats too much fuel. i have many customers with 25kw whole house gennys that run all day/night long when know body is home. ideally i would get an 1800rpm 4 pole genny but they are crazy expensive

 

[5030]

Interesting thread. With my diesel standby, neither horsepower or torque really matters. What matters is the rpm the engine is turning the armature at, which in my case is 1800 rpm.

 

[workinonit]

Maybe not but what does "matter" is load, specifically, sizing the generator for your specific load. And even more specific is to make sure you have enough head room above normal loads to start any inductive loads you may be driving. Second is frequency. As you stated, the gen needs to run at rated speed or bad things happen. If those things are squared away, voltage should not be an issue.

 

[5030]

Usually the genny's engine is sized for maximum output amperage. As the load increases, the physical resistance to the rotating armature increases and the engine works harder to maintain the correct rpm. Most all of them can surpass rated output for a short time as in starting a large electric motor. I know when my screw compressor starts and the genny is running, I can hear it grunt for a second, when the inrush amperage is high. Same with the Quincy reciprocating compressor. Both have 8 horse capacitor start, induction run motors. In rush is about 3 times running amperage.

With an inverter it don't matter so long as the electronic frequency generation is capable of providing the correct amperage and frequency.

Most inverter genny's have multiple pole heads, as many as 9 or 10. I guess the cost of them (Inverters) kind of limit them for heavy use as every one I've seen are about 2500 watts or less. Never saw a 3 phase one either. All single phase.

Never got into the mechanics of either of them, inverter or conventional, so long as they work, I'm good with that.

 

[Sawyer Rob]

Honda makes/sells some bigger inverter generators...

SR

 

[Smokeydog]

Years ago I got a small digital led plug in volt meter. Keep plugged in over the coffee pot in the kitchen. Use to watch the voltage change from 108 to 118 @0600 on cold mornings. Lights brighten and refrigerator hum changed. Now have 3phase at the road and underground 1/2 mile at the house. Steady 121-122V. Significant decrease in power outages at first but now becoming more frequent I think from the tremendous building boom.

What is a good hertz gauge to monitor utility and generator power? I see one brand of pto generator that has AVR option. Is that better? Cleaner power? Over a Winco?

In running a mower with a newer diesel tractors and watching the rpm I can’t tell if the engine is governed. Hold a rpm with varying load. One does have auto throttle option. The older and gas tractors I could easily tell. The newer ones might too? Don’t operate stationary equipment any more.

 

[Sawyer Rob]

I'd bet there isn't a tractor made today, that doesn't have a governor.

In fact, I've never owned a tractor of ANY age that didn't have a governor!

SR

 

[California]

An aspect I haven't seen covered in this thread: That tractor was capable of its rated PTO output when it was new - 35 years ago in the 1980's. To expect that performance now it will as a minimum need the cooling system brought up to spec, ie radiator boiled and rodded. Also I would replace all the hoses. Lets assume the water pump is as good as new. And I would do a major 1,000 hour service - Torque the head, adjust the valves, drop the pan and clean the oil pickup etc. - before expecting that elderly tractor to withstand running at its rated hp, continuous.

And I would add the low oil / overheating shutdowns mentioned above.

I hope its not a hydrostatic PTO.

 

[5030]

An aspect I haven't seen covered in this thread: That tractor was capable of its rated PTO output when it was new - 35 years ago in the 1980's. To expect that performance now it will as a minimum need the cooling system brought up to spec, ie radiator boiled and rodded. Also I would replace all the hoses. Lets assume the water pump is as good as new. And I would do a major 1,000 hour service - Torque the head, adjust the valves, drop the pan and clean the oil pickup etc. - before expecting that elderly tractor to withstand running at its rated hp, continuous.

And I would add the low oil / overheating shutdowns mentioned above.

I hope its not a hydrostatic PTO.

Interesting comment. Just had my open station M9000 at the dealer for it's scheduled overhead adjustment and injector spray / pop test and when the tech got done he put it on the PTO dyno and it's making a shy bit over 10 horses more than what Kubota rates it at. I asked him about that and he said no 2 tractors in the same model / engine range will dyno the same. It has just a tad over 6000 meter hours on it. Excellent oil pressure, starts right up, no smoke unless I'm working it hard. I've always taken good care of it just like all my tractors. I expect it to go at least 10,000 hours with nothing needing rebuilt. It's a 2002 btw.

One of my farmer buddies has a 4020 JD Diesel and he's rolled over the hour meter on it. I don't believe he's done anything major to it either, just normal maintenance.

 

[5030]

Honda makes/sells some bigger inverter generators...

SR

Was not aware of that but then I'm not in the market for ANY new generator.

 

[LittleBill21]

Was not aware of that but then I'm not in the market for ANY new generator.

you can parallel inverter generators (even regular ones) i think you can go like 14k 240v on dual honda's

 

[5030]

Went and looked. Honda's max out at 9K peak watts for a huge price. The HF inverters beats that at 1/3rd the cost.

 

[LittleBill21]

Went and looked. Honda's max out at 9K peak watts for a huge price. The HF inverters beats that at 1/3rd the cost.

you didn't look well.

https://imgur.com/5uTSuNI

 

[5030]

you can parallel inverter generators (even regular ones) i think you can go like 14k 240v on dual honda's

The thread is about PTO genny's not stand alone.

Honda's are way over priced anyway.

 

[5030]

you didn't look well.

https://imgur.com/5uTSuNI

So you pay huge bucks have two engines to maintain too. Pointless in my view but then I have a 30KW diesel standby anyway and my 30KW installed was less that 2 of those Honda's. Again, the thread is about PTO genny's so your comments are irrevelant.

 

[RalphVa]

I just bought a 15K watt generator which I will be putting on a 12K watt circuit. I will be attaching it to a Mitsubishi 180D three cylinder diesel tractor. The tractor has a three speed PTO. Running at the standard 540 setting, the engine will run at 2200rpm which is close to the max horsepower speed. If I run the PTO at the mid setting, then the engine will run at 1600rpm which is close to the max torque speed for this engine according to the owners manual. Which option should I choose for stable sustained operation?

Whatever gives you the right voltage and cycles.

 

[90cummins]

It depends how many kw’s you need. If it was during the day when there was a large load I would run at 2200 rpm. If you needed minimal power let’s say thru the night i would use the slower engine speed to conserve fuel. I wish my tractor had multiple PTO speeds.
90cummins

 

[rScotty]

We live in an area that loses power on a regular basis. Three or four days without power is not unusual.
Depending on the cause - and it's often weather - while these things are happening is exactly when we need both a tractor and a stand alone generator.
The stand alone gen has the economy of operation and the critical frequency control that the tractor PTO lacks.
Tying up the tractor for several days to make electricity doesn't make any sense. Even a Honda is better. Actually, the Hondas are a lot better. Very popular and for good reason.
I have yet to see a good argument that favors a tractor PTO generator over a simple stand alone generator.
rScotty

 

[Sawyer Rob]

I have yet to see a good argument that favors a tractor PTO generator over a simple stand alone generator.
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 is...

SR

 

[LouNY]

Cost per KW,
versatility in power sources,
any tractor with a decent governor which most have will control frequency quite well,
No screaming little gas engine to worry about,
no need for gasoline storage,
POWER POWER and POWER I have a 25KW generator depending on which tractor is on it
I can produce up to that amount of power reliably and consistently.
When it's only producing 5KW the fuel consumption is less then when producing 20 KW.
You enjoy you little screamer, I'll enjoy my diesel keeping my lifestyle consistent regardless of the utility power.