Low-Energy Light Bulbs & Inverters

here is what one maker has to say about it:

Here are a few pointers about which kind of inverter to use:

In general, any device that senses either voltage peaks or zero crossings could have problems when running from MSW. Devices such as these should be run from TSW inverters. Ham radio and CB radio operators may notice RF noise from MSW inverters; in that case do not run the radio and the inverter at the same time. Electronics that modulate RF (radio frequency) signals on the AC line will not work and may be damaged. You may notice hum or buzz in the audio of TV's, radios and satellite systems used with MSW inverters. Audiophiles or professionals using sophisticated audio, remote measurement, surveillance or telemetry equipment should use TSW.

Examples of problem devices are motor speed controllers employing triacs, and some small battery rechargers that do not incorporate a transformer between the utility power and the load. To help you visualize this, if there isn't a 'wall wart' between the battery charger (or the battery in the device) and the AC plug, don't use MSW.

Please note two other common problem loads, electric shavers and emergency flashlights. Both of these items have batteries in them but connect directly into the wall to charge, without an external transformer. Don't use items like these with an MSW inverter. If you do use an MSW inverter with a transformer-less charger, your product will likely be damaged. Garage door openers, laser printers and large strobes used in photography have all been reported as trouble loads for MSW inverters; they either don't work at all or stop working entirely, so don't take a chance - use TSW.

As a general rule, products operating through an AC adapter will work fine from an MSW inverter. These include laptops and cell phone chargers, video games, camcorder and digital camera chargers. Televisions generally work well; some VCR's with inexpensive power supplies run poorly. Consider switching to another brand of VCR in that case.

Regarding modied SQUARE wave inverters (the terminology depends on whether you sell them or buy them!)

I think that most peak-sensing loads will work fine. That includes switch-mode computer power supplies. After all, the first thing they do is charge a DC bus up to the peak value, so what difference does the wave shape make?

I agree on the zero-crossing devices. They will be in trouble.

I would be careful with wall warts, chargers, or any appliances that use a linear power supply (transformer/diode/capacitor). The transformer is likely to run much hotter due to the harmonic voltage content. Switch-mode types, such as laptops, should be fine, since they rectify first, so harmonics don't matter.

Ben Miller

Won't it depends on the use that is being made of the zero crossing?

If it is purely being used as a supply-derived clock, I would have thought it would be fine.

please note that this was a reply to a question on sep 5, 2005 where i merely offered what information a manufacturer had to say about the subject.

the original question is as follows:

here is what one maker has to say about it:

for the convenience of the poster i added the text to the reply.

Thanks, I only have an incomplete thread here.

I did "lose" an auto transformer, running it on a 110V 60Hz nominal supply, stepping it up to power a 240V 50Hz nominal TSW UPS. Years ago and in Haiti. Wondering what killed it has always been lurking in the back of my mind, ever since. Until now...

Of course what happened was that everything was working fine, when the transformer was powered by Haitian mains power. The TSW UPS was an online type and quite happily ran of a 60 Hz supply, generating a 50Hz supply...

But the mains supply must have gone off during the night and then back on before I woke. The building's inverter would have taken over and that will be what killed the transformer...the main inverter was an MSW..Of course the UPS kept the load going. So, in the morning I found a dead transformer and the UPS running on batteries.

Up until now, I had rationalised things into the theory that the UPS (a

1000W one) load must have gone up during the night. It was only running at 65W load. The poor little transformer was only rated at 300W (all I could find in Port au Prince at the time). But I couldn't find any evidence to show that the load would have increased.. I put it down as unexplained - but shortly after the inverter was replaced by a genny and a 2kW transformer arrived from the US..

There you go. Isn't usenet wonderful? Even at 1:15 in the morning it solves riddles..

My fault. I didn't notice the date on it!

Ben Miller