Generator Will 27HP run generator?

[Soundguy]

I agree with pretty much everything that has been said. I offer another word of caution. You must keep the frequency of your generator close to 60 Hz (maybe +/- 2 Hz, not too sure) . If you are running motorized applicance (wells, refrigators, air conditioners, etc.) and the frequency is off you can damage the motors. I suggest getting some kind of frequency meter (Kill A Watt at $40) to monitor this. You can plug it in in the house or at the generator to set and watch the frequency. I have heard of rashes of equipments failures caused by off frequency settings. I don't know how good the speed regulator is on the tractor, so I don't know the severity of this issue, but it is not costly to monitor.

Good advice.. however.. if his tractor's governor is ok.. he should be fine.

I ran my 12.5kw northern genny onmy old 1952 8n. I checked it with a few thousand watts of load.. mostly incandescent, and a few 10+ amp motor starts, plus radio and tv. I had a freq counter and VOM plugged in.

Freq was actually more stable on the gen output than my utility line .. same with voltage.. and that northern uses only capacative regulation.. active would be even better.

Soundguy

 

[aesanders]

Jim,
I don't understand why they don't make the recommendation based on PTO HP. Then, as you point out, since my PTO HP is 20: 20*.746 = 14.9KW. The rated PTO HP is presumably at 540RPM.

Most PTO generators are recommended based on pto horsepower. Sounds true for this one as well 15k for 30 pto hp tractor.

 

[RoyKing]

Heat is what kills generators, melts the insulation of the windings. Generator life is shorten when they have to output anything over 60% for long periods of time. Mecc-Alte owners manual goes through disassembly for cleaning and bearing wear check, and when/how to change the bearing. When buying Diesel genset the motor and Alternator will have kva ratings for peak and continuous. Oversizing the Alternator is a good practice like a 36kva Alternator and 30kva engine. As diesel run at 75% will outlast a Alternator at 75%.

I just finished a tank breather/dryer model after the expensive cartridge blue silica gel type. Has two check valves at 1/4 pound opening pressure with 2lb of gel in a clear 4" pvc pipe. The tank inhales and exhales through the gel and when changes color you can remove the gel and reheat it. Cost the same for parts as buying one, but don't have buy new gel cartridges. In Florida with tank outside under the gen the day to night temp swings are pretty high which makes tanks less than full breath a lot.

 

[Spiros]

Mark, I run my 13kw Northern generator with an old Yanmar YM1900 19hp engine and no clue how much pto hp. It will run my entire house but i do turn off the 5kw hot water heater and no clothes dryer use. It runs the house AC unit just fine.

 

[Tractor Seabee]

To prevent accidental overloads that could ruin something I recommend you plan all your essential loads and move into a separate panel only the generator feeds and uses one of the manual change over devices from the main panel. Then you can be sure a motor starting will not drag things down or trip a breaker. I have never gotten involved in a PTO generator so have no clue how speed is set and maintained constant.

Is there a device that maintains voltage and frequency by auto adjusting the engine speed. Even my 17 KW generator does not adjust speed rapidly, there is a little lag time but it has an internal voltage/frequency regulator of the engine. All gen sets I have used or worked with have the auto setting capability. Some of our military generators were 500-1000 KW with synchronization of several in parallel.

Does using a 40-50 HP tractor to power a <30HP load eat a lot of excess fuel where a separate gen set to match the load would be more efficient? I have always wondered about that.

Ron

 

[CobyRupert]

Mark, I run my 13kw Northern generator with an old Yanmar YM1900 19hp engine and no clue how much pto hp. It will run my entire house but i do turn off the 5kw hot water heater and no clothes dryer use. It runs the house AC unit just fine.

To prevent accidental overloads that could ruin something I recommend you plan all your essential loads and move into a separate panel only the generator feeds and uses one of the manual change over devices from the main panel. Then you can be sure a motor starting will not drag things down or trip a breaker. I have never gotten involved in a PTO generator so have no clue how speed is set and maintained constant.

Is there a device that maintains voltage and frequency by auto adjusting the engine speed. Even my 17 KW generator does not adjust speed rapidly, there is a little lag time but it has an internal voltage/frequency regulator of the engine. All gen sets I have used or worked with have the auto setting capability. Some of our military generators were 500-1000 KW with synchronization of several in parallel.

Does using a 40-50 HP tractor to power a <30HP load eat a lot of excess fuel where a separate gen set to match the load would be more efficient? I have always wondered about that.

Ron

Hopefully Mark has his generator by now and isn't still shopping for one. Seeing how he posted this in 2006.

Ignoring inefficiencies/losses for the sake of simplicity:
Tractor Seabee, the power that the generator produces, and the engine driving it produces, is determined by the how much power the load is consuming at that instant, not the "rating" of the generator or the motor. The motor and generator are only producing the power required to match what the load is consuming (and to overcome inefficiencies/losses).


That is, if the load is 240V, 50 amps = 12 kilowatts = 16 horsepower. The generator will only provide 50 amps/12 kilowatts (even if its a "20kw rated generator"), and the engine is only outputting 16 horsepower (even if it's a 30 HP engine). You're not eating a lot of excess fuel.

The details are in how the efficiencies change (worsen or improve) as you move closer or away from the "rating" (sweet spot of the power/torque curve, etc...) of the motor (and generator).

 

[Sawyer Rob]

Using a small tractor to power a bigger pto generator is NO problem at all, I do it quite often with my Winco pto generator, that's rated 15,000 watt continuous...

As long as you follow the rule, 2 pto hp per 1,000 watts, any modern tractors governor, will keep the pto at the proper speed to cover the load.

For bigger loads, I put a bigger tractor in front of the generator, but I can pull about 6,000 watts out, with the pictured tractor.

(for high loads or continuous duty, you should keep the pto shaft straighter than I had it in the above pict.)

SR

 

[attract her]

Interesting topic.

Some SUPERB comments, #3 & #6 included.
To #11 I'll add:

W/ PTO driven generator I gather there's not feedback from frequency (Hz) to throttle. Thus to keep the A/C frequency at 60 Hz may require a tractor throttle adjustment each time the load changes.

Thus I've concluded:
The more sensible move would be a self-regulating generator.

AND !!

While the topic starter may have an ample supply of diesel on hand, I believe there are commercial generators with diesel engines.
But for those that don't have a diesel tank in the ground, Propane (LP) may be the way to go, as it is a relatively safe fuel to store in bulk (doesn't contaminate groundwater).

And if you're going to try that, Generac or some similar unit may make sense, as they're designed to cut in automatically when the commercial power drops.

Do as you wish, of course.
But if you go PTO, bear in mind your emergency power "solution" may turn into a hobby, where you have to hop out of bed and adjust the tractor throttle every time the refrigerator or deep freezer cycles on. I prefer to put the electricity in charge of that.

PS
Neighbors have mentioned to me the manifold benefits of, I think he called them "inverter generators". It seems they're of benefit if a computer, television, or other sensitive electronic unit will be in circuit.

And finally, among my trailer camping friends, it seems to be a consensus that Honda makes the best generators for that purpose.

Good luck. Enjoy our Independence Day !

 

[LouNY]

Of the half dozen different tractors that I have used on my pto generator none have required throttle adjustment for minor load changes.
Mine is a 25 KW pto generator, I have run it with tractors at the 540 rpm pto speed,
I have also used it on 1000 rpm ptos at half rpm, some tractors could handle it with a stable frequency, some not so good.
One of my tractors has the economy mode which allows the engine to be at about 2/3's pto speedd and still be at 540 on the pto,
this is the one that I prefer to use, my second choice is a large tractor using the 1000 rpm pto at around half speed.

 

[TerryR]

While the topic starter may have an ample supply of diesel on hand, I believe there are commercial generators with diesel engines.
But for those that don't have a diesel tank in the ground, Propane (LP) may be the way to go, as it is a relatively safe fuel to store in bulk (doesn't contaminate groundwater).

And if you're going to try that, Generac or some similar unit may make sense, as they're designed to cut in automatically when the commercial power drops

We live at the top of a steep quarter-mile gravel driveway in snow country, so our propane supplier installed a 1000-gal. tank so they wouldn't have to deliver in the winter. Choosing a tri-fuel generator running on propane was a no-brainer. No worries about fuel going bad, and no worries about trying to get more fuel during an outage caused by conditions that make getting more fuel difficult. Ours predates the ready availability of auto-start systems, but it does the job well enough.