Generators

I have got a generator (Generac BSP7500LE) connected to my house (Via a proper transfer switch!)
When running from this generator, there is a very noticeable flicker on the lights all the time.
I have a tester, and it tells me the voltage is 230v and 49.8Hz when the generator is loaded at about 10A - what am I getting this flickering on the lights, and can I do anything to stop it!?
I have three UPS' on various computer equipment, and they seem happy with the generator's supply.
Sparks...
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Probably your waveform is nothing like sinusoidal.
Most equipment should cope OK with this.
Do you have a 'scope you could check the waveform with? (Assuming you know how to do this safely of course - don't even attempt it if you don't)
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Why would you expect this ? A generator is an electromagnetic machine with a great big iron core. There's little in there to cause harmonics and there's a great bit LR filter to damp them out. Inverters are your culprits for angular waveforms, not electrical machines.
In my almost negligible experience, flicker from generators has usually been caused by switching in crude electromechanical regulators.
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snipped-for-privacy@is.invalid says...

Incandescent or fluorescent?
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says...

Incandescent, the fluorescent ones are fine :)
Sparks...
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Incandescent lamps grossly amplify small supply variations as much larger variations in their light output.
--
Andrew Gabriel

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Time to change the remaining bulbs, then! You don't really want to be wasting expensive generator fuel on inefficient vanity bulbs.
Christian.
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the
the
I have the same phenomenon with filament bulbs running off my 6KVA 2 pole generator (3000rpm). Its because the generators speed is not actually constant due to there only being a power stroke every 4 revolutions of the crank and the lack of adequate inertia in the rotating mass to maintain the speed- thus you;re not getting a proper sinusoidal waveform.
1500rpm (4 pole) or 960 rpm (6 pole) alternators or even the new crop of inverter-generators dont generate this flicker.

Mine doesnt want to know. :( Its a Belkin . Dont know why, the supply volts & hz are within tolerance on the box. Any ideas?
Tim..
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Tim.. wrote:

It's a Belkin ...?
This is the same brand that sells gold-plated modem cables in Dixons that are faster than ordinary modem cables?
Owain
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Tim.. wrote:

It's a Belkin ...?
This is the same brand that sells gold-plated modem cables in Dixons that are faster than ordinary modem cables?
Owain
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Don't blame companies for making something that idiots are prepared to spend extra for. They're just responding to demand. How else would fashion companies survive otherwise?
--
"The road to Paradise is through Intercourse."
[email me at huge [at] huge [dot] org [dot] uk]
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On 8 Sep 2005 08:59:25 GMT, snipped-for-privacy@ukmisc.org.uk (Huge) wrote:

OK then - can I blame Belkin for my big pile of failed USB hubs ? They're firmly on my list of suppliers from whom I'll never willingly buy another product.
I might even _admire_ their chutzpah in selling gold-plated carrot embossers through Dixons. But why should I want to buy such a product ?
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Tim.. wrote:

I've sometimes run a 2000VA UPS off a 2200VA generator (I know...). The UPS takes a good long look at the generator output, and when it's happy it switches over. The generator sees the sudden load and its speed drops, and the voltage with it. The UPS doesn't like this, and disconnects. The generator speed shoots up. Hunting continues indefinitely.
To start the whole business I've taken to resting a finger on the generator's governor until the UPS switches over, forcing the speed very slightly high. That's enough to stop the UPS dropping out, and it'll run until it's out of fuel.
I reckon a generator engine needs a gurt big flywheel. But at least I can drag this one around. Honda sidevalve, made in Thailand. I dread to think when it was designed but it starts on the first pull every time, no matter how many years it's been lurking without attention in the shed.
Nick
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Sparks wrote:

I'd be interested to hear the true answer. Its not wave shape, a filament lightbulb can run off any wave shape, and with the power level varying at 100Hz (which is what you get on a 50Hz supply) the filament will smooth it all out no problem.
The lighting flicker you see on gennies sometimes is at much lower freq than 50Hz, so the genny's output must be in some way modulated at a lower frequency. I dont know what the cause is, but the only likely candidate I can think of is the control circuitry, the regulator, where one is fitted.
If youre determined to get rid of the problem, there are 2 solutions, excluding genny replacement.
1. changing to CFLs will help, as their output varies much less with v. Traditional fluorescents ditto.
2. Putting big reservoir caps on the CFLs will wipe out the problem completely. Full wave rectify the power to the bulb socket and add your big cap there. It will be compatible with all CFL and filament bulbs then. Note youre not allowed to do with with screw in holders, since it leaves both connections live.
I get the feeling I have explained not very well here...
NT
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snipped-for-privacy@meeow.co.uk wrote:

I agree. The genny will have an AVR module (automatic voltage regulator) which senses the AC output voltage and adjusts the (DC) current in the field windings to stabilise the output. Thus there's a negative feedback loop involved and all the usual loop dynamics and stability issues are present. If the loop is underdamped and there's a varying load on the genny you get 'hunting' of the o/p voltage, which is exactly the "modulation" you describe.
--
Andy

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On Thu, 08 Sep 2005 23:44:06 +0100, Andy Wade

ISTR noticing as a small child the lamps on fairground rides and sideshows being modulated the same way.
DG
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wrote:

No, I doubt the OP's 3000rpm small petrol Genny will have an AVR, it'll just have a passive system of a cap and 2 diodes in the field winding. My 6KVA certainly doesnt.
Only the vastly more expensive larger 3000rpm and 1500rpm sets will be equiped with an active electronic AVR, which do keep the volts more stable, especially if they are 'slugged' somewhat. This doesnt help the frequency though unless its fitted with an electronic throttle. (i.e. 40kva and bigger ish)
Tim..
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Mine is also a 6KVA set, maybe this one would be a bit better? http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&itemD04176390 Do you think this would have the active electronic AVR?
Sparks...
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Damn, they don't take paypal :-(
Moving on a bit, I'm interested in the running costs of your genny's. How many kW/h do you guys reckon to get to the gallon (or pint?) from a 5-6kVA unit (petrol or diesel)?
Pete
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