Light flicker vs Engine Speed (Single cylinder)

[veggie]

Does anyone have any experience with light flicker as it relates to single cylinder engine speed ?

My 6/1 Listerloid at 650 rpm creates constant flicker in the house lights. This was to be expected... but it is annoying.
I also don't want to supply this dirty power to my high efficiency (electronic controlled) gas house furnace.

The head is a Voltmaster 3600 rpm unit with voltage regulation, so I am confident that the head is of good quality.

I have a few options to replace the listeroid with faster running engines.

1 - 900 RPM Chanfa 195
2 - 2200 rpm Changfa 175
3 - 2600 rpm Air cooled F186

Does flicker usually disappear at 900 rpm ? or do I have to go higher ?

[Henry W]

Over 22 years ago I've experienced watching flickering on a Listeroid 6/1 turning a 3600 RPM generator head with fair load. It was awful. A mater of fact it was so bad that it was giving me a headache.

This was one of the reasons I've abandoned the GM-90 project back in 2008 and decided to go with an S195 driving an ST-10 belted 1 to 1.

But, when I pushed the S195 to pull over 8400 watts I noticed slight flickering. But that engine was running well over its recommended load.

I ran my Kubota EB300 near 2200 rpm driving a 3600 rpm head putting out 2000 watts and I noticed no flickering. I've ran sensitive equipment and they had no issues. The generator head has a skewed rotor or stator. I'm not sure which one it has. This feature could clean up the power some.

I would try running the R175 at 2200. If you get a flicker than go up to 2400.

I do know that the Kubota EB300 I have is spec'd to operate at 2600. And the engine seems to like that speed. It pulls a 31 amp load (3700 watts) and will hold it. But, I would not run that load for very long. The Kubota has no problem pulling over 60 amp momentary surge. But I'm using a 10.5 KVA head hooked parallel putting out 120 volts only.

I do know the Kubota EB300 can pull a 25 amp (3000 watt load) for hours without being stressed. I'm still running tests to determine how many hours I would consider to be the limit at this load.

I do know that the Kubota will pull a 20 amp (2400 watt) continuous load. Once the auxiliary filter is installed with the additional sump I would say it will be ready to run continuously for days if needed.

The Changfa R175 is similar to the Kubota EB300. I would think  the R175 would do everything you would need. And, you can easily try different speeds to see what works best for your needs.

My pick is the R175. Start at 2200 and see how it works. If not sure, go up a couple hundred RPM.

[veggie]

Good info Henry, thanks.
The R175 is probably the best option.

One other thing occurred to me. If I want to keep the GM90 in this service (House emergency power), there is one other option.
I have a small 24 volt battery bank and a Magnum 4024 (4000 watt) split phase pure sine inverter kicking around.
I could mount the 24 volt alternator on the GM90 and have it charge the battery bank whenever the inverter is needed.
The magnum inverter can connect to my transfer switch as if it were a generator head plugging into it.
I would have the engine running whenever the inverter is in use thereby pulling power right from the alternator into the inverter using the batteries as a voltage clamp for the system.
(Both alternator and inverter connected to the bank)
This would give me flicker free pure sine power for the house.

A listeroid inverter generator 

cheers !

[veggie]

Like this....
[ click to enlarge ]

[Henry W]

Your welcome veggie,
A 24 volt alternator with a pure sine wave inverter would be your best option for the GM-90.
I think you will be pleased with this type of setup.

Hey! You have a GM-90! Just wanted to make sure that you know what you have. That engine is better than any stock listeroid I played with.

Cheers !

[Henry W]

Like this....
[ click to enlarge ]

Yea, like that.

But correct the typo's.

[Henry W]

After thinking about your drawing I feel you would have tremendous surge Capacity. The batteries will buffer a large momentary surge that would normally start loading an engine up.

Does the 4000 watt inverter have a higher surge output than its continuous rating?

Looking forward seeing more on this future project.

Henry

[Tom Reed]

I like the inverter idea too, lots of advantages there. However there are also a lot more components to fail too.

Flicker is probably at least twice as bad with a 3600 rpm head vs. 1800. At a given load a 650 rpm Listeriod will have the flywheels slow down x rpm between power strokes. Because a 3600 rpm is belted at twice the ratio of a 1800 rpm head, it will also have twice the speed change. And then the rotating mass of a 1800 rpm head is higher it will reduce the speed change more.

On my system, good led or cfl lights don't flicker at all, cheap ones flicker a lot.

[veggie]

That's interesting Tom, I had not thought of that.
I do have an ST-3 1800 rpm Head that I could try on the Listeroid before doing any bigger changes.
I will have to look into that.

[veggie]

Tom,

I just did the math. Look at this ...

Lets assume that the engine pulse (or speed drop) is the equivalent of 2 rpm at the engine.

ENGINE RPM      RATIO         GEN. RPM
=======================
650                   5.53              3600
648                   5.53              3583 <---- a drop of 17 RPM !


Now lets look at and 1800 rpm head...

ENGINE RPM      RATIO         GEN. RPM
=======================
650                   2.77              1800
648                   2.77              1794 <---- a drop of 6 RPM

So an 1800 rpm head has less than half the rotational interruption.
However, we can see that even the 1800 rpm head has a 6 rpm bump in it's rotation.

Where can I find a 1200 rpm head?   

[Henry W]

An 1800 rpm head will reduce flicker but unfortunately not enough to get rid of it. The S195 belted 1 to 1 driving an ST-10 at 1800 rpm pulling the load that I mentioned earlier still made the lights flicker. And it was still annoying. My concern would be that if your eyes can pick up the flickering, what effect will the flickering have on modern electronics?

I would think the idea of a 24 volt alternator tied with a battery bank driving a pure sine wave inverter would be the way to go. I like the idea of not having to worry much about monitoring engine speed. And, the ability to possibly reduce engine speed some when low loads are being used. To me it seems like there will be less monitoring. And, less of a chance of frying sensitive electronics.

Henry

[veggie]

Yes, the Changfa 195 and the Listers both have a fairly hefty POWER stroke and this jerks the belt drive with every revolution.
I tend to agree with you Henry. The system for cleanest power is a Lister Inverter Generator.

Cheers

[Henry W]

For now the R175 running at 2200 or 2400 rpm driving a 3600 rpm head will most likely take care of your needs.

Here is something else to think about. And, I always wanted to do this years ago.
You have an 1800 RPM ST-3 generator head. Use the R175 to drive it.
For example: 5.5" pulley on an R175 driving a 7" pulley on an ST-3 will allow the engine to run near 2292 rpm's while the generator is producing a 60Hz frequency. This setup would also greatly reduce rpm drop and might also increase a ability of the engine to pull more of a load on surges. And a tighter hold of a 60Hz frequency should be noticed.

[Henry W]

Veggie,
I've been thinking,  this might be a good time to move forward with modifications of a Prestolite 110-555 JHO alternator.

The GM-90 should work very well for such a project.

I've been seriously thinking of going this route on my next project. It just makes sense.

If I can get my hands on a good 3000 or 4000 watt pure sine wave inverter that is affordable I would do a refit on the Kubota project I'm working on. I purposely made the engine pad to allow for changes and upgrades

[veggie]

Henry,

Fortunately I have a brand new Delco 26si, 24 volt alternator which is used on large equipment like semi-trucks and earth movers.
I intend to start out with this one to get things up and running.
The 110 jho does seem like a good project for future use.