Generator/Back up Sine wave questions

[MHannon]

I posted this in lighting, filtration, and other equip. Nobody seems to know what im talking about.

I know that regular household AC power from a powerplant comes in as a true sine wave, and that a battery back up, such as a marine deep cycle battery(DC) hooked up to a power inverter comes out as AC. Im guessing that this is not a true sine wave, probably modified or simulated sine wave?

Also, does a generator put out DC or AC? Im guessing it would have to be AC since people use them to run household items. And would this be a true or modified sine wave? Are big outdoor generators meant to power a house any different in this manor than a smaller Portable generator?

I keep hearing people say not to run items with computer chips on on anything but a true sine wave. Meaning dont run your lights with an electronic ballast, but pumps are fine. Is this true?

Sorry I have a lot of questions, but I am kind of confused. Can someone explain this to me?

 

[billsreef]

It all depends on the inverter or generator. You can obtain ones that will do any or all of the things your asking about. You just have to check the specs on what ever unit your looking at. The ones that put out a true sine will definitely say so, as it's a marketing plus for anyone wanting to run computers or other sensitive electronics off of an inverter or generator. If the unit doesn't mention anything about the subject, than it's only good for simple things like pumps, refrigerators, household lighting etc.

 

[matt_54351]

here is an excellent thread that covers most of the topics you were inquiring about

"emergency power"

http://www.reefcentral.com/forums/showthread.php?s=&threadid=1277722

 

[BeanAnimal]

Generators put out AC.

Generators come in many flavors. Some output a nice clean sine wave, others don't do such a great job due to bad voltage regulation. The wave form is still a sine wave, but it may be noisy with spikes in it. The "big" generators that are meant to power a house during an outage have nice clean outputs (at least the good units). The $150 2000W genset from the local chicom outlet is not likely going to have a clean output.

Inverters and UPS systems are a different beast. Most put out an approximation of a sine wave. It appears chopped or squarish. The better the inverter, the more true the sine wave.

Computer power supplies are "switch mode" power supplies and work off of the "switching" of the signal. They could really care less what the waveform looks like as long is at swings from +/- at 60 cycles.

Motors and ballasts are another story. They rely on the smooth transition from +/-, not the absolute timing of the peaks and valleys. They don't work very well (if at all) on a square wave. They can overheat, catch on fire, or cause the UPS/inverter to fail (or catch on fire).

 

[S_Stoney_S]

I agree with the computer not caring less about your sine wave. I run an in car pc on a inverter and it has to survive cranking etc...

 

[MHannon]

Ok, thanks for taking the time to explain this to me.