Hello there,

Any one ever use one of these things?
These are devices that raise or lower the line voltage depending on the current line voltage. For example, if the line goes down to 90vac it will still put out about 120vac, and if it goes up to 140vac it will still put out 120vac, approximately. Supposedly they also filter to make the wave cleaner.

When they post the spec's they are not that detailed. They spec for example 89 to 140vac input. That means that any input voltage like that will cause an output voltage of close to 120vac. But what happens if the line goes down to 80vac, or maybe even 70vac? Does it attempt to bring the line up higher, maybe to 110 or 100vac, or do they cut out?

 

They spec for example 89 to 140vac input. But what happens if the line goes down to 80vac, or maybe even 70vac?

It fails to supply the proper 120 volts.

 

Yes your output voltage goes down as the input drops below its minimum rating.

 

When they post the spec's they are not that detailed. They spec for example 89 to 140vac input. That means that any input voltage like that will cause an output voltage of close to 120vac. But what happens if the line goes down to 80vac, or maybe even 70vac? Does it attempt to bring the line up higher, maybe to 110 or 100vac, or do they cut out?

Operation outside of the spec'd input is not supported. Depending on the design innards, that can mean a sag in the output voltage, a total cutout, or a fire. In one sense it doesn't matter what might happen; rest assured that if the device could handle a wider input range or more power, it would. There are several technologies for this type of device ranging from a switching power supply to a really big transformer, and for all of them the input current goes up when the input voltage goes down. It is the maximum input current that sets the power limit.

ak

 

I use a LC1800 (old style metal case) on the output of my main solar inverter to run an AC unit. It's just a tapped auto-transformer inside so it's limited by that but it does help with large motor surges when the compressor starts.

 

Hello again,

How did you find out it had a tapped auto transformer inside?

I guess what i was trying to establish was if the unit would run under the specified voltage even if that meant the output would drop when normally it isnt supposed to.

For an auto transformer it sounds like it would just drop, not cut out, unless the current was too high of course.

For example, the Tripp Lite conditioners all seem to be spec'd at 89 volts ac min. That is still kinda high for around this area where it can drop to 80v in the summer time.
But lets say it is 89 volts, and it puts out 120vac exactly up to that low point. With an auto transformer with several taps it would have switched to the highest tap by then, so it would be putting out the max that it can at 89v which is 120vac, and that is a ratio of 1:1.35 approximately. Now say it drops to 80vac input rather than 89vac. I guess that means the output would drop to 80*1.35 which is about 108vac which would probably keep most things still running somewhat normally. At 70vac input it would be 94.5vac output, which is still a lot better than 70vac.

So if this is the way it works that would probably be ok. But they dont seem to specify that on the web sites.

 

But they dont seem to specify that on the web sites.

Probably because they don't want to get into specifying the consequences of a max. input current limit. If a regulated power supply is connected to the conditioner output, its input current will increase as its input voltage sags. So a conditioner might be able to drive a 1000 W load at 90 V but only 850 W at 80 V. And is it watts or VA? Given that a lot of these devices are used by people who don't understand these terms the way an EE does, there's a point where admitting something is possible causes more problems that it does sales.

ak

 

Hello,

Well thanks but, i dont care what their reasoning is, i need to know this information regardless how they feel about it

 

the large ones work pretty well, tapped transformers with motorized taps, movable cores, and such. the ferroresonant type work pretty well, but beware of large transients when the power input changes repidly, a place I used to work for used some 1.5 kva ones to help uot video games at an airbase when the hangar doors opened and closed. ocasionally blew power supplies in them too. a real good one was located at a place I was in back in the 70's in the army, an electric motor spun a 7 ton flywheel and switched to generate if the power dropped. after a littloe while, it jerk started a diesel. the whole thing would loose less than one cycle when the power went out.

 

Looks like a constant voltage transformer, without the suppression http://www.alliedelec.com/images/products/datasheets/bm/SOLA_HEVI-DUTY/70098576.pdf

 

Thanks Gerty. Lots of data in that file.