Flicker flicker

[veggie]

As we know, flickering lights is a common experience with 6/1 engines driving an ST3 or ST5 head.
I am wondering if anyone using an 8/1 or a 10/1 is experiencing the same thing being the these engines can run at 750 to 850 rpm ?
Wondering if the slightly higher engine speed eliminates the flicker?

cheers,
veggie

[buickanddeere]

Any harmonics at work that are in sync with 50Hz, 60Hz and the number of power strokes ?

[32 coupe]

I was thinking the other day about the fact I have never had any other load on my listers other than a
space heater or 3.
I will go so far as to say that my changfa clone (24 hp--15kw) still has a fair amount of flicker.
I will amble off now ......

[millman56]

I run a Dursley 6-1 driving a Sincro 4 KVA 2 pole (3000 RPM) alternator, the alternator has been retrofitted with a Chinese AVR which was working well until a week ago, the voltage started drifting down over a days run and strip lights were flickering at 4-5 Hz,  it turned out that the UFRO trimmer had somehow lost its setting,  adjusting the UFRO, Volts and stability trimmers brought it back to normality without discernible flicker although the voltage on a light load drifts down from 238 to 226 or so over a days run.  
It would seem that my flicker was AVR induced.                                                                                                                                                                      My thoughts are that due to its 2 X higher speed hence greater inertial mass a 2 pole alternator will not be as affected by low frequency power pulses as a 4 pole one.  Veggie does your flicker increase linearly with increased load or is it constant?  Any physicists out there?

Mark.

[veggie]

What I am getting at is this...
I recently wired up the house with a transfer switch and I plan to install my ST5 head on the listeroid.
At this point I have not selected the belt drive so my engine speeds are flexible.
My GM90 Listeroid can run anywhere between 500 and 900 rpm (of course the BHP output changes with speed).
I am happy with the KW output with the engine running at 650 but if speeds upwards of 850 rpm eliminate flicker then I
can run at a faster speed.

So... I am wondering if anyone with an 8/1 or 10/1 (which typically run between 800 and 1000) is noticing flicker with an ST head ?

veggie

[Combustor]

            Lister's original SOM sets had heavier "electric" flywheels on them, plus an additional flywheel built into the generator pulley, and at least with the Lister generators flicker was never a problem. My 8/1 SOM is rock steady with fluoro or incandescent lamps, though output voltage does vary somewhat in proportion to the total load.
        Not easy to find heavy flywheels, but could be worth trying the extra mass on the alternator pulley. Would not be hard to take a car engine flywheel and machine it to locate and bolt up to the alternator pulley to see if the improvement was worthwhile. Recall someone here doing it in the past but don't recall the final conclusions.
        Regards,  COmbustor.

[listeroil]

I have run both 6/1 and 8/1 Startomatics with the heavy flywheels and the 6/1s flicker and the 8/1s don't. The flicker is quite noticeable on the 650 rpm engine especially with incandescent bulbs for some reason. I have seen other 6/1 engined sets with flicker as well. One other thing I can say is that the Startomatic generators do not have AVR. I believe the ST generators don't have one as well. An AVR might help.
Mick

[32 coupe]

Seems I recall BruceM saying that the flicker was reduced when he went from a 5kw to a 3 5kw head
I seem to think he is running a 6/1 at about 650
He uses his all the time I believe
perhaps he will chime in and add his input.

[BruceM]

I run my 6/1 at 650 rpm, with the spoked flywheels and an ST-3. 

Without my homebrew AVR, the flicker was unbearable.  With my AVR, the flicker is bearable on incandescent lights of 100 watts or more.  (My shop heat lamps are 250 watts and are not bothersome at all.)  Lower wattage bulbs do noticeably flicker a little even with the AVR.  This is not a problem for me as I use 120VDC for my home and shop lighting, except for the 2000 watts of heat lamps which I sometimes use in the shop in the winter.  I did notice the voltage variation problem on my custom designed 120VDC battery bank charger; the voltage variation showed up as DC charge current variation which I had to filter out to avoid confusing my Picaxe controller.

In comparisons using a circuit I made to look just at the low frequency AC voltage variation, my 6/1 with  AVR performed comparably to a 6/1 with SOM flywheels and no AVR.  You will get a bit more flicker with the ST-5 head, despite the extra rotating mass, as the larger rotor inductance makes for slower changes in output voltage.  A simple AVR can only do so much, since it cannot anticipate the 10Hz power pulse, and the delay caused by the rotor inductance is significant.  In theory, a microcontroller should adaptively be able to anticipate the power stroke effects and provide some of the correction early enough to allow for the lag in rotor inductance.  No one makes an AVR that does this for slow speed engines, since it is such a tiny market.

More rotating weight and higher rpms are definitely a good idea, so I would vote YES, on bumping up the speed, yes on adding an AVR and yes to adding more mass to the generator shaft (1800 rpm makes that quite useful).  I'd also be watching for SOM or heavier flywheels.

Some of the better quality compact fluorescent bulbs will do electronic regulation such that incoming voltage variation is of no concern, likewise some electronic ballasts and some LED lights.  A design which advertises a good power factor will more likely be one which does a good job of regulation.  I can't tolerate fluorescent or LED lighting so can't help much there.

Best Wishes,
Bruce

[buickanddeere]

Hanging a "large" DC capacitor across the + and - lines to the brushes may reduce some flicker caused by excitation variances.

[Tom]

To confirm Bruce's reply, on my 6/1 st5 spoked flywheel system, the better quality CFL and LED bulbs have no detectable flicker what so ever. No AVR here either.

[38ac]

We have two set ups, one with a 'roid running just under 650 RPM and the other powered by a Chinese single at 1800. Only difference I can tell is the faster running engine has faster flicker. Neither set up is beyond the basic ST, I dont even have the AVRs hooked up. Personally I find the less intense but faster cycling 1800 RPM flicker to be more irritating than the 650 RPM flicker. My sons hate the 'roid flicker but hardly notice it when we run the Chinese powered unit.  Funny thing is the wife notices neither one. Really, she doesn't know what I am talking about and she is far from a non-particular type person. 

Why bring this up? I have concluded that flicker is an individual thing. If true it could very well  be why we can read on the forum where one fellow did "X" and fixed his flicker problems while others report doing same and it did nothing whatsoever??
 
Just for your considerations 
Butch

[mike90045]

My Metro, 6/1 spoke flywheel & st5 head with bridge diode (no AVR) has flicker with just about every light, except for DC LED's  
  But it's not too bad.

PS
The garage door opener will not work on listeroid power, but the brains on the propane stove will.  The propane stove brains will not work on the robin/subaru/hatz generator, but the garage door opener does !!!

[BruceM]

I agree, 38ac, people's response to flicker is highly variable and individualistic.  If you only have to satisfy yourself, and you are not  significantly affected, shifting the engine rpm to a less bothersome frequency (change in generator pulley size)  might be a viable approach for some. 

If someone really needs it I can try to dig up the simple rectifier- low pass filter circuit I used to measure the low frequency variation in AC voltage. 

Most new electronics power supplies are so broadly tolerant of voltage variance that other than lighting, or UPS units which are closely scrutinizing the power frequency and voltage to detect a dropout, there should be no problems with Listerflicker. 

A simple photodiode, 9v battery, resistor and an o'scope will let you confirm that your CFL or LED is not flickering just below your perception.  The better quality designs will be regulating the lamp current, and line voltage or line voltage variation (including Listerflicker) will have have no effect on the light.  You could also visually confirm this with a small variac.  In a good lamp design, you should see no variation with a fairly wide range of input voltages.

[cujet]

I run my twin at 800RPM with a 15KW ST head. It certainly produces "unclean" power. I have a small O-Scope and it clearly displays a few issues. One is the unusual sine wave shape. The other issue is the amplitude of each sine wave is different.

I purchased a voltage regulator from GA Generator in an attempt to improve my sagging voltage. It will be interesting to see if it helps the unclean power.