Generator PTO generator speed

[dodge man]

Say you have a PTO generator that is meant for a 540 RPM tractor PTO. Say your tractor is suppose to be 540 rpm at 2600 rpm engine speed. This is more or less wide open or close to it. What happens to the generator output if you run you engine speed at say 2000 rpm. Do you still get 110 volts out of the generator and it will just carry less load?

 

[jeffinsgf]

No, that's a truly bad idea. What will change from the lower RPM is the frequency of the power. In other words, everything in your house is designed to work at 110 Volts (or 220 Volts) at a frequency of 60Hz. At a lower RPM you will be producing power at a lower frequency, say 50Hz, which will cause everything to run hot, slow and inefficient.

My generator has a frequency meter on it. It hits a perfect 60Hz when the tractor tach is right on the little mark for 540 PTO.

Your tractor was designed to run wide open all day and all night. It ain't a car engine. Don't worry about it. Throttle it up to where it is supposed to be and don't burn up all your appliances.

 

[atgreene]

I had to add a freq. meter to my pto generator to keep it where it needed to be. The 540 mark on the tach was not accurate. Once I added the meter and could set it where it belonged at 60 hz, the pump, boiler motor etc... were much happier with me. Even the computer would work, through a ups, of course.

Here's the link to the one I bought. PTO Generator Pricing

And likewise to what Jeff says, these tracotrs aren't kids toys. Set it where it belongs and let 'er run. Much better for the engine to not be stumbling and playing catch-up with the governor when the well pump or furnace kicks on.

Good luck.

 

[RonMar]

What Jeff said

Freq is RPM dependant. A typiucal generator will most likley put out lower voltage if undersped. This is also known as a "Brown Out". Brown out's are VERY bad for electrical and electronic devices. A PTO genny needs to be run within 10% of the PTO RPM of 540 to produce adequate power.

 

[Soundguy]

Ditto all that... run the genny at rated rpm.

Now.. if you had a tractor that had an economy pto setting for small pto loads, and you had enough hp to run at a lower engine rpm, then you could make that work.. but those are alot of "if's"


soundguy

 

[johan3400]

dodgeman,
it appears you may get a chance to test it out with the ice storm moving into western Illinois. Run that tractor to the rated rpm for pto. It will run for days and days with no problems. Tell us how it works if you loose power. I am sitting listening to rain falling on the roof outside and the temperature is 20. I hope we change to snow soon. We have the tractor hooked to the genny and ready to move into action. I hope that is enough insurance to ward off the ice storm. Good Luck

 

[atgreene]

If you don't have a hertz meter, find an old clock with a second hand. Plug it into the genny and run it until you find the rpm that runs the clock at exactly 60 seconds per minute. That will work in a pinch.

 

[JB4310]

That's a great tip, only problem who has a plug in clock with a second hand any more?
Does the 60 HZ have anything to do with 60 seconds in a minute?

 

[atgreene]

Clock runs on a motor that is geared and calibrated to run on 60 cycle electrical a/c power thus will turn at 1 minute per revolution. Speed up the hz and it will turn faster, slow down the hz (speed of the generator) it will slow down. Kind of archaic way to do it, but it works.

 

[Tom_Veatch]

...Does the 60 HZ have anything to do with 60 seconds in a minute?

HZ or Hertz is the official, scientific term for "Cycles per Second", like "Amperes" or Amps is the term for electrical current ( A bit of useless information: 1 Ampere = 1 Coulomb per Second flowing past a given point. 1 Coulomb = 6.24150962915265 x 10^18 electrons).

AC (Alternating Current) in the US is standardized at 60 Hz. The voltage alternates from maximum positive to maximum negative and back to maximum positive 60 times per second.

 

[LBrown59]

Where is your tractor going to be setting through out an ice storm while it's powering the Gen.?
This is just one of the problems I see with a P T O Gen.!
L . B .

dodgeman,
it appears you may get a chance to test it out with the ice storm moving into western Illinois. Run that tractor to the rated rpm for pto. It will run for days and days with no problems. Tell us how it works if you loose power. I am sitting listening to rain falling on the roof outside and the temperature is 20. I hope we change to snow soon. We have the tractor hooked to the genny and ready to move into action. I hope that is enough insurance to ward off the ice storm. Good Luck

 

[jeffinsgf]

If it's really coming down, I've got a tarp I can throw over it. Flip the seat forward to keep it reasonably dry in case I need to use it. I've got two tractors, either of which can run the generator.

Remember, again, this is a tool to be used, not a museum piece. In 90+% of the cases, your tractor spent the first few months of its life exposed to the weather. One or two nights in a storm isn't going to cause any malfunction.

 

[atgreene]

Where is your tractor going to be setting through out an ice storm while it's powering the Gen.?
This is just one of the problems I see with a P T O Gen.!
L . B .

Mine is sitting in the same place it always sits. Why, is your allergic to rain or ice?

 

[RickB]

I don't have a hertz meter, or the intentions to buy one. I do, however, monitor the AC voltage at an outlet in the house while the PTO generator is running. My rig needs to be run a little below PTO speed to maintain proper voltage values.

 

[jeffinsgf]

Do what you want, Rick, but your electrical devices are more sensitive to variation in frequency than they are to variations in voltage.

 

[Tscott9330]

Not to hijack, but my tractor has 2 PTO settings one is the standard 540 and the other is 1080 (I think thats right). The dealership told me it was for over seas and not to use it. Could I set the PTO to this position and run at half the RPM to get the 540 RPM needed?

Tom

 

[PILOON]

Not to hijack, but my tractor has 2 PTO settings one is the standard 540 and the other is 1080 (I think thats right). The dealership told me it was for over seas and not to use it. Could I set the PTO to this position and run at half the RPM to get the 540 RPM needed?

Tom

Mine has 3 PTO rpms, 550, 700, 1000(1080?) and I often use the 700 with my snowblower basically because I am gear driven (not HST) mainly to get a bit faster ground speed in lighter snow conditions.
I also use it in heavyier snows at slow speed for blowing the snow farthur, doing that for 8 years without any problems.
Mind you I never let the engine bog down.

 

[djradz]

Do what you want, Rick, but your electrical devices are more sensitive to variation in frequency than they are to variations in voltage.

Jeff, I'm going to have to respectfully disagree. In fact, many devices are rated 50/60 Hz, because they'll do just fine either way. What typically burns up (non-resistive) electrical equipment is low voltage which results in low power so the equipment ends up drawing significantly more current to drive the load.

One thing to note, with most of the capacitor excited generators on the market today, the voltage (up to rated load) will very much fall in line when the frequency is adjusted to ~60 Hz and vice-versa. As such, adjusting for the voltage is usually a fairly accurate way (+/- a few Hz) of setting up the generator.

One side note: There is a device called a "Kill A Watt" available that runs about $20-$30 and can be plugged into any outlet to give you not only Hz, but all kinds of other power useage information. It's designed to help you track how much power a particular device, such as a freezer, is using over time, but it has the added bonus of frequency, voltage, current, power factor, among other measurements. I got mine on eBay, but they're available elsewhere. They also make an advanced unit that costs more and has some added features, but I'm not familiar with it.

 

[JB4310]

Not to hijack, but my tractor has 2 PTO settings one is the standard 540 and the other is 1080 (I think thats right). The dealership told me it was for over seas and not to use it. Could I set the PTO to this position and run at half the RPM to get the 540 RPM needed?

Tom

This comes up often, the short answer is yes for light loads, but it really depends on your tractors pto horsepower in relation to the gennys out put. If you had a 100hp tractor and a 10 kw gen, then you could probably draw the full 10 kw off the gen at the lower engine r's. But if you have a 14 pto hp machine and a 7 kw gen, you would not be able to draw much off the genny at lower r's due to well due to many factors but the main one being you need that full 2 hp per kw and to get and keep the gen in the sweet/safe spot as far as volts/HZ output goes. This is not the best description as to why not but I'm having trouble putting in an easy explanation, others will be able to.

Definitely the # 1 PTO generator question/Issue.

Whoever told you the that 2nd speed pto option was for "over seas" should get the Bozo of the year award and should not be selling tractors.

 

[Tscott9330]

This comes up often, the short answer is yes for light loads, but it really depends on your tractors pto horsepower in relation to the gennys out put. If you had a 100hp tractor and a 10 kw gen, then you could probably draw the full 10 kw off the gen at the lower engine r's. But if you have a 14 pto hp machine and a 7 kw gen, you would not be able to draw much off the genny at lower r's due to well due to many factors but the main one being you need that full 2 hp per kw and to get and keep the gen in the sweet/safe spot as far as volts/HZ output goes. This is not the best description as to why not but I'm having trouble putting in an easy explanation, others will be able to.

Definitely the # 1 PTO generator question/Issue.

Whoever told you the that 2nd speed pto option was for "over seas" should get the Bozo of the year award and should not be selling tractors.

My rig is a 42HP Branson. I do not have a PTO Gen but hey, maybe some day.

So is the 2nd PTO speed for any particular implement? What is the primary use?

Tom