Generator PTO Generator - Lights Flicker

[teg33]

You are correct on my wiring situation, #6 to #12. This was a temporary setup to test the generator. The lights flicker worse at a light load (4.1A one side, 6.7A other side) which shouldn't be affected by this wire size.

Now it may be possible that the small wire is preventing the problem from going away completely at my higher test load (about 29A on each side) which includes resistive and motor loads.

I also learned from Tiger that this smaller size generator does not have an active voltage regulator, it relies on capacitor regulation. We have tried changing the capacitors with no improvement.

Can anyone answer my earilier "governor" question? What type of governor is on the B2400 and how well does it regulate the engine/PTO speed at various loads? Could it allow a fluctuation up and down (oscillation) in the PTO speed as it regulates?

Thanks

 

[teg33]

Can anyone explain the Kubota governor?

What type of governor is on the B2400 and how well does it regulate the engine/PTO speed at various loads? Could it allow a fluctuation up and down (oscillation) in the PTO speed as it regulates?

Thanks

 

[SnowRidge]

I know nothing in particular about Kubota governors, but I'll bet it's a mechanical flyball device. In any event, if the lights were flickering because of changing frequency (RPM), you should be able to hear it. If as you say, the frequency meter is correct (and steady), then that too would pretty much rule out generator RPM as an issue.

So that leaves voltage sags/surges. You said the voltmeter reads normal and you have put an o'scope on the line and can see nothing wrong. That doesn't add up.

If there is any kind of voltage or frequency instability of a magnitude great enough to be visible with a light bulb, it should be easily be visible on the scope, so why isn't it. I guess we need to know a little more about how you are checking the output of the generator.

Are measuring the voltage at the light bulb socket? What kind of meter are you using? What are you using to read THD? What kind of o'scope are you using? What sweep and sync settings are you using? What powers it? Not the circuit under test, I hope.

Working theories without knowing more:

1. The generator has crappy voltage regulation, especially under light loads, and it is hunting. You are seeing the result.

2. There is a resistive leakage path at the transfer switch or elsewhere, and you are seeing phase differences between the generator and the utility power.

 

[Soundguy]

I rather think the pto shaft not equaling a constant velocity joint is / may be a factor.

My capacitive regulation on my northstar 12.5kw genny is fine with a single 100w lamp plugged in. course.. my genny is mounted on a cary-all, and the tractor pto runs straight out to the genny input.. no angle, and no bends for the pto yokes to make.. etc... perhaps this is a bigger issue than it would seem to be?

Also makes me wonder if the pto type is having a factor.. I.E. a tractor that has a built in ORC may not suffer as much as one that doesn't when looking at the pto angle and the velocity of the shaft.. that is.. if the shaft is speeding up du to an angle.. it may not have to 'slow' down on the downside of the rotation if the tractor has an ORC, as the shaft will be able to overspeed.. whereas a tractor with a non live/non independent pto may lead/lag the pto shaft making that oscilation more noticeable?.. just a theory..

Soundguy

Soundguy

 

[SnowRidge]

If it was due to angular differences on the PTO, wouldn't the flicker have to be at a rate of N(PTO_RPM)/60, where N is the number of velocity changes per revolution. It seems like N would be either 1 or 2, but I haven't thought it out. Assuming a 540 PTO, it should mean a steady flicker rate of either 9 or 18 HZ. A rate like that is observable and could be computed with the aid of a stop watch.

If the calculated rate was 9 or an even multiple of 9, it would tend to confirm the theory.

Edit: I'm not thinking straight, and I oughta quit while I'm behind -- as my wife likes to tell me. A 9 HZ rate may be observable, but it isn't countable without test equipment, at least not accurately. /forums/images/graemlins/crazy.gif /forums/images/graemlins/blush.gif /forums/images/graemlins/crazy.gif

 

[Soundguy]

Got to have some fast thumbs.. but yeah.. that's the idea. Also to throw in the mix .. I had been thinking about genny poles and 1800rpm vs 3600 rpm.. but after thinking.. it doesn't muddy it that much, as if the pto angular problems are happening.. then it will still be a multiple that you could track.

Soundguy

 

[Dutch445]

When you say the lights "Flicker",
can you describe it more accurately?
Is it a constant flicker, every few seconds,

or once a minute,

and once it's doing it, does it stay constant
until increased load is put on the generator?

and i'm way over my head here,, but thought I'd throw
this in...
is there anyway to eliminate that 50' lead and get the
generator closer to your transfer switch?
/forums/images/graemlins/confused.gif

 

[teg33]

Sorry I missed all this input but had a long day. Here's some more...

- I ruled out the PTO shaft alignment, checked it again and everything is straight as an arrow.

- I tried to attach a video clip but couldn't create a useful file less than 100k. The problem is more of a pulsating than a flicker, I'm estimating 3 pulses per second worst case with light load. If this were a governor caused fluctuation, I gotta believe you could hear the engine difference, which I do not.

- Measurement tools were a Tektronix TDS3054B Digital Scope and Fluke 83B Power Quality Analyzer, both with calibration stickers and powered off house current. Probes connected at transfer switch before the house subpanel. I'll attach a sample plot or two of the worst case.

- I could eliminate the 50' lead BUT I did connect a gas powered Coleman through this same connection and had no problem with flicker. To me, that should rule out the lead unless it is somehow interacting differently with the PTO gen.

Thanks again

 

[teg33]

The worst case plot with a larger time scale. Note what appears to be some amplitude modulation on the waveform.

 

[Soundguy]

Wow.. is that a brush or brushless unit?

The first pic showed what? 63.x hz,.. that's way unacceptable. Nice waveform too -not-.. reminds me of modified.. I tested my northstar output with a freq counter and graphing fluke vom.. came out with a 'perfect to the eye' sine wave.. as far as the pixels on the scope looked... and a rock steady 60hz, Heck.. measuring my house line... I got an occasional 60/61 reading, and more voltage fluctuations... House ran between 114 and 130 depending on what was running. Genny ran pretty near 119/120v...

Soundguy

 

[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.