Is Pure Sine Wave always necessary?

[lkruper]

I have been looking at putting together a combination of charger, battery bank and inverter for emergency backup. The good manufacturers like Samlex sell both pure sine wave inverters and msw. Of course psw is much more expensive. Last year at Black Friday I bought a few small APC UPS backups. I was concerned that the computer equipment I wanted it for would not work or work properly but I got them anyway. I tested them on my computers (Acer) and found no problems. I now have two of them on broadband modems and one on the Acer. No problems. If I had purchased pure sine wave modems I would have paid much more.

So now, I am looking at expanding my protection with a home-built system that will handle longer outages with off-the-shelf batteries. My gut tells me that my Sony 32", sound bar and Directv receiver won't have any problems.

When I got my transfer switch installed, I brought up to my electrician that I had a pure sine wave generator. He had the same switch and also a generator at his home. He had no idea what a pure sine wave generator was and said his generator ran everything in his home just fine.

I have heard refrigerator compressors might not work or work as well. I have heard that some battery chargers might not work, etc. However I have not heard any specifics, such as model X of Y does or does not work.

So, what is the worst that can happen to get a MSW inverter? Can it ruin the items? Will I be able to tell right away that something does not work?

[Naptown]

Motors in general do not like MSW
most electronics however run on DC and have rectifiers built in that make it a moot point

[sensij]

http://www.samlexamerica.com/support/faqs/faq02.aspx#question_4

[Mike90250]

Motors last longer on Pure sine wave.

if you are going to use a Transfer Switch for a mod sine inverter to your main panel or sub panel, expect a fiery show, mod sine inverters generally cannot have a leg grounded The manual for the inverter will cover that more.

[PNjunction]

So, what is the worst that can happen to get a MSW inverter? Can it ruin the items? Will I be able to tell right away that something does not work?

The reference that Samlex shows is excellent first of all.

The worst that can happen is that a device may *seem* to run with no problems, but may in fact be just approaching the MTBF (failure) much faster than normal. You may just end up replacing things sooner than expected.

Personally, with PSW being relatively inexpensive compared to years ago, the ONLY things I run from MSW inverters are lights. I tend to like running multiple inverters for different functions, rather than having just ONE available. If that sole inverter smokes during an outage, your entire backup system is for naught. Not only that, but with multiple inverters, you can size them for efficiency better depending on what loads they are handling.

The classic mistake here is a guy using a 1Kw 12v inverter to charge a cell phone.

[lkruper]

http://www.samlexamerica.com/support...spx#question_4

First of all, thanks for all the excellent responses. This samlex article is really excellent. I provides the reasons things don't work in a very understandable way. Also, there is something I did not think about that I think this article addresses. I have security cameras that make a network over my AC line. It sounds like that won't work and I never thought about that.

[Leehamrick]

It may sound crazy but my T.V. works much better when running off a sine wave inverter than it does
when I'm on the grid. -- Picture is much better

I'm in desolate spot in the mountains the electric here is down on a regular basic

[Wakie]

I run everything at my cottage with a MSW inverter.
Led light with little flickering.
Freezer with no problem in 2years.
Tv picture is not as good as with my generator
Toaster no difference
Drill run hotter than normal
Radio have poorer reception and humming noise , to the point i got a dc radio
Cell phone charger is slower
A run a 2000 watt inverter on 24 volt battery and it draw only 10 watt
It s your choice to have a PSW inverter

[PNjunction]

Samlex makes some of the rf-quieter inverters. Note that they also provide power supplies designed primarily for amateur radio use, and thus know about noise issues.