New generator and lights turning on

ForeverAg

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9:51p, 7/8/24

AG

This outage is our first time with our new whole home Generac 26kw generator.

We have recognized that the generator throttles up a bit when our largest AC turns on, and when it does lights that are off at the switch light up. Specifically two can lights in our ceiling flash on then back off though the light switch is clearly in the off position and untouched.

How concerned should I be with this?

Picard

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9:52p, 7/8/24

AG

Are they on dimmers? If so, wouldn't worry about it.

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ForeverAg

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In reply to Picard • 9:56p, 7/8/24

AG

Picard said:
Are they on dimmers? If so, wouldn't worry about it.

Yes they are on a dimmer, why would this be happening?

We have other lights in the same gang box also on a dimmer and they do not flare up.

Jason_Roofer

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3:21p, 7/9/24

Are these LED lights?

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ForeverAg

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In reply to Jason_Roofer • 5:11p, 7/9/24

AG

Yes they are. They are the blue box brand from Home Depot in I believe a Par30 size.

Jason_Roofer

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In reply to ForeverAg • 10:34p, 7/9/24

ForeverAg said:
Yes they are. They are the blue box brand from Home Depot in I believe a Par30 size.

OK. I don't have anything useful to add but I will say that LED lights seem to do some WIERD things that are supposedly perfectly OK. I added LED lights to my old pickup, and at night, when it's dark, when I turn my turn signals on, the LED lights in my doors 'blip'. Incandescent don't do it, but LED will. Someone else will have to explain it, but I can say that I have noticed things like you mention with LED lights all the time. There is JUST enough current running to light them up even if they are 'off'.

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Picard

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10:40p, 7/9/24

AG

Same here.....can't quite explain it beyond dimmers are "screwey". Understand that dimmers work by manipulating or cutting out the voltage many times a second. That normally works fine, but when the input voltage is unstable they can wig out a bit. Another example is dimmer lights cutting in and out during a big thunderstorm due to instability on the power lines.

Hopefully someone EE degree here can provide a more technical explanation.

BenTheGoodAg

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In reply to Picard • 10:53p, 7/9/24

AG

Quote:
Hopefully someone EE degree here can provide a more technical explanation.

In all my years as an EE, nobody has ever said this.

I think it could be a few things, but the dimmers are likely the best explanation. Modern dimmers modify the input sine wave which is created by the rotational speed of the generator. The modern power grid is very rigid, and the sine wave is very consistent at 60 rotations per second (60 Hertz). By comparison, a small isolated back-up generator is more likely to get pushed around by the loads, so the rotational speed varies when you add or remove load, which causes the sine wave to vary. Since dimmers are designed for 60 Hz, they don't play well with these variable frequencies. Combine that with the really low load of LEDs, and they behave unpredictably, which is why some lights may come on and others don't.

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