Author Topic: Modified Sinewave Inverter  (Read 2324 times)

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bruce

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Modified Sinewave Inverter
« on: June 06, 2005, 10:03:28 PM »
     I bought a new Aims 24vdc to 120vac inverter, 2500w constant use. Lightning retired my old 2000w inverter, it was a Powerbright. Any time keeping device worked fine on the old one. Now on the new one, it seems like a better inverter in alot of ways, but any time device runs fast, I'm talking an hour a day. I have one clock and 2 wall timers that are gaining time fast. The clock I can live with, but the timers are just that, timers. I need things to kick on and off at certain times, and now thats impossible. I was real happy with it all until I found that out. What are my options? Anything I can filter easily on maybe just that one outlet that the timers are plugged into?

     I've emailed the company with no response back yet. I've heard of this happening, whats actually the reason the time runs fast?


                                      Thanks alot, Bruce

« Last Edit: June 06, 2005, 10:03:28 PM by (unknown) »

sandovalch

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Re: Modified Sinewave Inverter
« Reply #1 on: June 06, 2005, 04:21:25 PM »
I have exactly the same problem with an Aims 2500W 12V inverter. Haven't had the time to figure a solution. My problem is not that big, since I obly have my alarm clock connected to it and before going to bed I adjust the time so I can get up on time in the morning.

The problem, seems to me that the frequency is not really 60Hz, but a tick higher. I have opened the inverter and in it you can find 3 potentiometers. But which is the right one? I did not want to change their setting.

Maybe someone else has a clue!
« Last Edit: June 06, 2005, 04:21:25 PM by (unknown) »

wpowokal

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Re: Modified Sinewave Inverter
« Reply #2 on: June 07, 2005, 07:29:36 AM »
Assuming this is a modified square wave inverter, it is possible that this is a harmonic problem ie superimposed on the 60 hz may be aditional waves that trick clocking devices.


The solution may be something as simple, as a correctly voltage rated capacitor across the inverter output to capture (filter out) these harmonics.


Allan

« Last Edit: June 07, 2005, 07:29:36 AM by (unknown) »
A gentleman is man who can disagree without being disagreeable.

alcul8r

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Re: Modified Sinewave Inverter
« Reply #3 on: June 08, 2005, 10:54:05 AM »
Interesting.  Are the clock and timers digital or analog, and do they all keep the same time?
« Last Edit: June 08, 2005, 10:54:05 AM by (unknown) »

nothing to lose

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Re: Modified Sinewave Inverter
« Reply #4 on: June 08, 2005, 07:19:37 PM »
That is the only problem I have with my 5K Aims inverter also, I think a digital clock radio gained about 4-6hrs over night. It was alot anyway, otherwise it runs everything fine.

Not a real problem for me so I never fixed it. Depending on what the timers are for etc.. a solution may be to find a cheap used sinewave UPS and run it for timers and clocks.


I have done lots of things playing around, some work and some don't. You might be able to run a UPS off the Aims inverter. The UPS might correct the power, clean it, and the clocks/timers then run correctly. Some Ups's will work ok, some may click and clack like they are kicking back and forth. Various combinations have worked for me and others have had strange results also.


I have about 6 Ups's I think and 3 or 4 various size inverters and changed tested alot of ways.

If you don't use the UPS on the batteries they should just stay charged and not much power loss for charging I think. It's still nice to have the backup available for some things incase the batteries get low or overloaded and the main inverter shuts off.


If you go the inverter route you may also be able to just run it off the batteries direct if you want and avoid the main inverter power. I have also done that too of course.

« Last Edit: June 08, 2005, 07:19:37 PM by (unknown) »

bruce

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Re: Modified Sinewave Inverter
« Reply #5 on: June 09, 2005, 07:15:57 AM »
     One is a digital clock/radio, but the timers are mechanical wall timers. They are the $5-$10 timers you just plug into a wall, set the dial timer, set your on/off times, then plug in the accessory into it.

     I've cant say they gain exactly the same amount of time since telling the time on the timers are not as exact as a digital clock, but I'd say they are about the same, about an hour a day, maybe a tad more.

     Everything else about the inverter is good, but this is frustrating, especially since my old one kept time. I called Aims and he couldnt exactly tell me why it happens, but said its normal. I asked about the Hertz, he said if it was out of spec they'd replace it, but I havent found a Hz reading multi-meter yet, I may have access to one today. I can post back after that.


                                 Thanks, Bruce

« Last Edit: June 09, 2005, 07:15:57 AM by (unknown) »

kurt

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Re: Modified Sinewave Inverter
« Reply #6 on: June 09, 2005, 04:59:56 PM »
if your clocks are gaining an hour a day then your inverter is running at 62.49HZ (my thanks to bobn for doing the math on that) thats probably well within factory specs for the inverter. clocks not keeping time is a common problem on inverters what you need is to buy 2 digital appliance timers that use an AA battery for the clock part and just the switching part is run off of line power they sell them at most hardware stores around here for around $25.
« Last Edit: June 09, 2005, 04:59:56 PM by (unknown) »

bruce

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Re: Modified Sinewave Inverter
« Reply #7 on: June 10, 2005, 07:32:38 AM »
     Spec books shows 60 Hertz, +/- 1 Hertz. I'm measuring 63 Hertz, which is making sense. Called the tech number, he said if its not in spec they will swap it out. He said they could test one there at the warehouse before they sent it out, which would be good. Right now they are out of stock, should have them in within a wk or 2, and it would be a new batch so they could be more refined. Or not. We'll see.


                                      Bruce

« Last Edit: June 10, 2005, 07:32:38 AM by (unknown) »