anyone run a pto generator with your crawler?

johnHD · Post by **johnHD** » Mon Oct 13, 2014 2:16 pm

Hi all,

just picked up a 20KVA PTO generator at a farm auction.

wondering if anyone uses their crawler to run one.

i have a 1955 40C, i figured i would try it and see if the crawler was easier on fuel than my 1020.

john

Tigerhaze · Post by **Tigerhaze** » Mon Oct 13, 2014 4:06 pm

I believe there has been a number of threads in the past discussing this, if you search for "pto generator".

Post by **Lavoy** » Mon Oct 13, 2014 6:46 pm

Done it many times, with different crawlers or Dubuque tractors, works fine. You will be short on HP to run that many KW, so watch your load.
Lavoy

johnHD · Post by **johnHD** » Mon Oct 13, 2014 9:39 pm

i don't plan on loading it up to the nameplate, i could turn everything on in the house twice and not hit 15 KVA.

it will be interesting to see how the govener on the crawler reacts to various load changes...

the general rule of thumb for HP vs. KVA is 1KVA = 1 HP, so in theory it should keep up.

john

Post by **Lavoy** » Tue Oct 14, 2014 7:06 am

You better figure 2HP per KVA, that is the most common figure I have heard on PTO units.
Lavoy

johnHD · Post by **johnHD** » Wed Oct 15, 2014 4:57 am

Thanks for the tip Lavoy.

It may be better run behind my 1020. Once i get some load on it i will have a better idea.

Ever have to flash the field coil on one?

john

Post by **Lavoy** » Wed Oct 15, 2014 6:41 am

1020 will be smoother power with the 3 cylinder, maybe a little sharper governor too.
No, always been able to just hook up and go.
Lavoy

Stan Disbrow · Post by **Stan Disbrow** » Wed Oct 15, 2014 7:56 am

Hi,

AC generators have two sections on the shaft. One is an AC alternator (obviously) and the other is a DC generator.

The DC gen has permanent magnets that start things off, with its own field coil and regulator, just like on our old tractors. But the magnets are a lot stronger than the mild steel plates in the old iron, so they do not lose their magnetism so do not need to be repolarized.

The output of the DC generator feeds the field coils of the AC alternator. I have seen some where the DC output can be plugged into to charge a battery if equipped with electric start. Not on a PTO one, though.

I have also seen some which need an external battery to start off the AC field coils, but only in certain industrial units. Those are called AC Alternators, BTW. It is the self excitation of the AC field which is why they are called AC Generators.....

One thing that can be an issue with a PTO AC Generator is the frequency of the AC. The gearing down of the engine RPM to the PTO and then up to the generator shaft speed has some slop in it which causes fluctuation of the frequency. This can be made even worse by the engine governor. And the fewer the cylinders, the worse that becomes.

The end result of too much fluctuation in frequency can cause some loaded AC motors to not spin up right and cut off while still on the primary (start up) windings. And refrigerator and freezer motors would be of the most concern there.

Something to keep an eye on when using a PTO generator for emergency backup.

BTW, the best sort of AC generator would be one directly connected to a 6 cylinder engine and wound to run at 1800 RPM for 60 Hz. That gives enough engine pulses to be consistent for a load on the AC and also a fast enough response from the governor for AC motor starting loads to keep frequency in range.

Not too portable without trailer axles under it, though. And even with, not as handy as being able to hook it directly to the back of the tractor to go build that shed on the far side of the field.

Stan

johnHD · Post by **johnHD** » Fri Oct 17, 2014 4:29 pm

Stan,

thanks for the info, it did turn out my generator had lost its magnetism in the shunt coils. i had about 5 volts of output.

i followed the instructions found here http://www.wincogen.com/files/downloads ... _field.pdf

i flashed the coils with a 12 v battery charger and it immediately started to work!

i let it run for an hour behind the 1020 with a light load on it with very steady voltage.

i will have to see if it keeps generating after i pull it out of the shed next time. this must be why they suggest running them at least once a year. mine appears to be 1967 or 69 vintage,

now to get to work on the transfer switch and give the generator an oil change and a greasing.

john

Steven Walters · Post by **Steven Walters** » Sun Oct 19, 2014 6:15 am

Defiantly have to figure 2hp for every KW. I bought 25kw pto drive gen that's set up for 550 pto and hook it up to 1000rpm pto. At a pinch over idle it will run full tilt and tractor dosent even know its there. I didn't get to figure fuel consumption but it has to be better than 10-15 gallons of gas per day in the little gen.

johnHD · Post by **johnHD** » Sat Oct 25, 2014 12:13 pm

Thanks for the tips steve, mine will need to stay 540 rpm.

I pulled it out of the shed again and it seems to be keeping its magnatism. Changed the oil and greased the PTO shaft.

Still shopping for a manual 200 amp transfer switch, i think i found a GE model that will work.

I have a couple of switches i salvaged years back but they are pole top models and this semi retired lineman doesn't want to climb to the top of my yard pole to troubleshoot it.

I needed a new voltmeter as the one that came with it was not working, I was able to find a guy in Illinois that had nice replacements for 12 bucks.

Interesting to discover once the voltmeter was working it takes about 10 seconds for the generator to make voltage once up to speed.

I'll post some pics once i find a new image hosting site.

john

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anyone run a pto generator with your crawler?

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