PTO or portable generator for whole house generator backup ?

[Sawyer Rob]

The general rule is, it takes 2 PTO HP per 1,000 watts.... SO, you 24 PTO will make 12,000 watts...

ANOTHER general rule is: for "continuous duty", (more than 30 mins continuous run time) you should not pull more than 80% of your max PTO power, out of your tractors PTO...

SR

 

[sixdogs]

Great responses. Thank you all.

What is "clean" power? Are older generators "clean" power in that if I bought a used generator at an auction, would it be trustworthy?

If I got a Winco that runs at 515 RPM, what if I don't get the RPM's exact. Does it matter?

 

[Jkott]

Great responses. Thank you all. What is "clean" power? Are older generators "clean" power in that if I bought a used generator at an auction, would it be trustworthy? If I got a Winco that runs at 515 RPM, what if I don't get the RPM's exact. Does it matter?

U.S. Power grid is 60 hz (think of. It as 60 rpm for your generator). If the input speed is off, and the output is a direct multiple of that, then the output frequency will be off too.

Motor speeds for things like drills and saws will vary with the frequency, but not care too much. Electronics tend to like a more consistent frequency.

 

[vsteel]

Great responses. Thank you all.

What is "clean" power? Are older generators "clean" power in that if I bought a used generator at an auction, would it be trustworthy?

If I got a Winco that runs at 515 RPM, what if I don't get the RPM's exact. Does it matter?

Clean power is generally defined as having less than 6% total harmonic distortion. (<6% THD) That is the general guideline for running sensitive electronics. Not only does the voltage and frequency that come out of a generator matter, how good of a sine wave you are going to get is important.

A lot of older generators do not give clean power because when they where made, most things they would power didn't have much in the way of electronics in them so it wasn't as critical. The digital age made THD more important.

You don't have to worry about getting the RPMs right on any generator from the tractor gauges. PTO generators will have some type of meter that will tell you when you are at the proper speed. RPM gauges can be off on tractors so you just use that as a guide to get close to the proper RPM, you will let the generator tell you when you are at the proper RPM. Just increase or decrease the throttle on the tractor until the needle is in the green. The RPM does matter and as you load the generator you might have to adjust the throttle to keep it in the green. That will depend on the size of the load and the HP the tractor has and how well the governor works.

 

[Baby Grand]

Clean power is generally defined as having less than 6% total harmonic distortion. (<6% THD) That is the general guideline for running sensitive electronics. Not only does the voltage and frequency that come out of a generator matter, how good of a sine wave you are going to get is important.

A lot of older generators do not give clean power because when they where made, most things they would power didn't have much in the way of electronics in them so it wasn't as critical. The digital age made THD more important.

You don't have to worry about getting the RPMs right on any generator from the tractor gauges. PTO generators will have some type of meter that will tell you when you are at the proper speed. RPM gauges can be off on tractors so you just use that as a guide to get close to the proper RPM, you will let the generator tell you when you are at the proper RPM. Just increase or decrease the throttle on the tractor until the needle is in the green. The RPM does matter and as you load the generator you might have to adjust the throttle to keep it in the green. That will depend on the size of the load and the HP the tractor has and how well the governor works.

Thanks, vsteel, for condensing all of the information, in your previous post, into a well organized, well written reference.
I've bookmarked this thread as a buying guide for myself.

 

[buickanddeere]

A 15KW generaror will make full power with 23pto HP. However there is no reserve for motor starting if demand exceeds 15KW .
As for consumer grade generators . Operating beyond 80% of rated current , particularly in warm weather is not recomended.
Check the fine print on the generator. Sometimes the capacity displayed in plain view is peak or momentary.

 

[buickanddeere]

What kind of plug, receptacle and transfer switch?

 

[Sawyer Rob]

A 15KW generaror will make full power with 23pto HP.

On paper that's true, but with all the loss' along the way to make that power, you really need more than 23 PTO HP...

SR

 

[sixdogs]

What kind of plug, receptacle and transfer switch?

In the past I used a GenTran transfer sub panel and an outside receptacle with a 30A 4 prong twistlock. That worked fine.

A while back, my electrician suggested a way that replaces a section of breakers on the panel and is technically a whole house 50A full power unit. I now have a 50A outside receptacle, a cord that connects into the basement panel. When the power goes out I have to flip a lever in the panel (to prevent backfeed) and start the generator. I then flip the breakers according to what I want to operate.
Power hasn't gone out since but I would rather have it and not need it than need it and not have it. You know the drill.

 

[buickanddeere]

In the past I used a GenTran transfer sub panel and an outside receptacle with a 30A 4 prong twistlock. That worked fine.

A while back, my electrician suggested a way that replaces a section of breakers on the panel and is technically a whole house 50A full power unit. I now have a 50A outside receptacle, a cord that connects into the basement panel. When the power goes out I have to flip a lever in the panel (to prevent backfeed) and start the generator. I then flip the breakers according to what I want to operate.
Power hasn't gone out since but I would rather have it and not need it than need it and not have it. You know the drill.

Excellent .
Those jackleg generator connections without an interlocking break before make transfer switxh . And/or using a double male suicide cord back feeding a welder receptacle are a disgrace.