Generator PTO Generator - Lights Flicker

[JoeR]

This really has me thinking. Let me throw out some thoughts...

Are you feeding your house with 220 or 110? Assuming 220 single phase and you have a two pole generator, check the phase of each 120v line and compare. Are they in phase? Your two channel O-scope should be able to overlay them.

Specifications say you can only have 20A for 110V or 60 for 240, but 50 amp breaker limits you to 25 per. Anyway, if your PTO can only support 7K, then you should not exceed 15 amps on any leg. So, make sure the current draw on any given 120v leg does not exceed 15 amps.

Is your PTO shaft too long? You could have flex in the shaft creating a rubber band effect. Is your mount vibrating too much?

Maybe the generator gear box is not right? A possible problem inside the gear box could create inconsistent speed on the shaft of the generator or a wobble. If they did not mount the generator true to the gear box, then you could end up with oscillation symptoms. You should notice excessive vibration especially at low speed. What if there is inconsistent spacing in one or two of the gear teeth? This would cause varying speed on the generator shaft.

Lastly, I remember some farmers complaining about two and three cylinder engines not giving a constant PTO speed under varying loads. Something about the torque, and there not being enough weight to maitain the momentum necessary to compensate for the change in load.

Anyway, I hope you find the problem so we can all learn from this.

Joe

 

[teg33]

The lack of 60Hz was my doing, we were experimenting to see if a bit higher engine speed would resolve the light flicker. It did not, and in fact made the problem worse. That is why I choose this plot to post, it had the worst flicker.

In fairness, if I set the speed for 60Hz, the generator did hold that frequency quite well, at least according to the meter readings.

I'm surprised you consider this sine wave "bad". I only have experience with a couple generators but this was the better one. This is a brushless unit.

Regarding your "perfect to the eye" sine wave... I'm not familiar with a graphing Fluke VOM but is the graphing feature equivalent to a high speed digital sampling scope? What sample rate and resolution does it have? It could be that the resolution and filtering was such that you could never see the finer details of the waveform, just a thought?

By the way, I did try the scope on house power and it looked very good, but not perfect.

 

[SnowRidge]

It looks like the generator output has something modulating it at roughly 3 1/2 HZ. Is that about the rate of the flicker? Might be a clue there, if it is.

 

[Dutch445]

I'd be asking for another Tiger unit and see what happens after you swap them out.
You can tell them that you aren't getting good even power
from this one and you want another one under warranty.
It doesn't sound like anything to do with the tractor, or wires, etc... just could be a problem in the generator, which shouldn't be your problem to fix!
keep us posted
/forums/images/graemlins/smile.gif

 

[teg33]

Alas, we may never know the answer.

I bought this unit used from a dealer and they have been working the problem with me. They have asked for the unit back to do additional testing (I believe on the generator head itself) and have offered a full refund, which I plan to take.

Many thanks to everyone for their help, I'm a bit gun shy now about PTO generators but will look for another, although I'll probably upgrade to an electronically regulated unit.

Thanks again

 

[burnetma]

Digging up an old thread.

I bought a Tiger Power PT010 in July 2006 to power my home during a 5 day power outage. I had the same issue with flickering lights. I should have returned the unit, but I got busy haying and other projects, so I never got back to the generator.

I tried all the fixes in the previous posts back in 2006 with no success at resolving the issue. Now I have to use the unit again for a construction project. Not worried about the quality of the power necessarily, but would like to know if there was ever a fix to this issue.

Note: No problem with having enough tractor in my case, as I ran it with my JD 5420 (65 pto HP).

 

[Treemonkey1000]

A honking big surge suppressor box or line filter network. With the voltage varying like that I would worry about any electronic items that might be powered by that. Even a Nicad battery charger will have electronics in it.

 

[tommu56]

Digging up an old thread.

I bought a Tiger Power PT010 in July 2006 to power my home during a 5 day power outage. I had the same issue with flickering lights. I should have returned the unit, but I got busy haying and other projects, so I never got back to the generator.

I tried all the fixes in the previous posts back in 2006 with no success at resolving the issue. Now I have to use the unit again for a construction project. Not worried about the quality of the power necessarily, but would like to know if there was ever a fix to this issue.

Note: No problem with having enough tractor in my case, as I ran it with my JD 5420 (65 pto HP).

Describe the flicker is it constant or when you put a load on it?

If its when you put a load on it it could be the tractor governor isn't "kicking in fast enough"

Another thought put some real like 1000,or 2000 watts load on it and see how it reacts.

tom

 

[burnetma]

The flicker is a subsynchronous pulse seen in incandescent lights. Possibly a couple a times per second. Kind of reminded me a a flickering candle. It was July 4th weekend, so I had the air conditioner, refrigerator, well pump all on at one point. The more load, the less the flicker, but it never went away. With only the lights on it was intolerable, so we shut it down and lived by oil lamp and candles, which really is no hardship.

Note: The unit was wired into the box through a disconnect switch using the 220 plug and breaker.

I worked with the alignment of the tiny generator to the big tractor in all three directions. I tried to brace the unit with hold-downs. I triple checked the lube in the gear box, which was somewhat noisey, but I have nothing to compare too. Greased the PTO shaft.

The entire time tractor was as steady as a rock RPM wise. Not even a slight change in pitch as loads were added and removed.

It has to be internal to the unit.

Tomorrow, weather permitting, I will get it out and work with it again. This time I will not hook it up to the house, but will run some other loads around the farm and see what happens. If no luck, it has a 5 year warranty...

 

[tommu56]

Then next thing to check is if it has brushes and the slip rings make sure the rings are clean a little oxidization on them will reduce the voltage to the field (the center rotating part on most of these gen's) and cause some odd problems.
Scotch brite the slop rings check the brushes to male sure they slide in and out freely.